Q: Are Webroot and Trend Micro the same? Is it harmful to have them on at the same time? Or is it a waste of money, and am I doing double security?

A: This is a good question. It reminds me of a scene from a Billy Wilder movie called Ace in the Hole. In it, Kirk Douglas plays a scheming reporter who tells his prospective employer that, "I've done a lot of lying in my time. I've lied to men who wear belts. I've lied to men who wear suspenders. But I'd never be so stupid as to lie to a man who wears both belt and suspenders." His point being that you can't slip one by a man who has redundant methods for keeping his pants up.

Back in the world of Internet security software, Web Root and Trend Micro are actually different Internet security products put out by different companies. You can read our reviews and see a comparison here. You actually should not have two Internet security products of any brand running at once. It's not so much that you're doing damage, but the products may interfere with each other allowing something else to damage to your computer. Instead of doing double security, you might actually be cutting your security down.

Webroot may do something that Trend Micro sees as virus-like activity, or vice versa. Of course, Webroot is not a virus, but its activities could be misinterpreted. At the very least, it's a bit of a resource drain. At worst, it could interfere in detection of an actual virus or firewall intrusion. So choose the one you like best and uninstall the other one.

In Ace in the Hole, it turns out that Douglas actually is lying. So, while Internet security software is neither belt nor suspender, the moral of the story is the same: sometimes being twice protected doesn't help at all.

Q:I received a Windows security alert and it directed me to have a scan of my computer which alerted me to numerous Trojan and viruses and worms.  Now I am not able to open any of my computer files or access my virus protection. Is this site legitimate or is it a scam?

A: It depends on where that warning came from. If it came from reputable Internet security software that you installed on your computer, it's probably legitimate. If it came from a website that you came across, it's probably a scam. Either way, it sounds like you probably have a virus, or some other piece of malware on your computer. A good antivirus product would have removed any viruses or advised you on further action.

A good first step is to try running a free scan from a reputable company, such as the one from Norton. This should give you an indication of what's going wrong. Depending on the quality and age of your antivirus product, you may want to consider upgrading to a more robust Internet security software product.

Q: I have a possible virus on my desktop. How will the McAfee process work and what will I have to do? I am not abreast on all the computer literate info. Can I do this my self or do you have tech support who can talk me through the process if i buy the McAfee total protection package? I want protection, firewall, spam, malware, phishing, virus, trojans. Please advise!

A: A few days ago, we talked about signs of virus infections and some of the free virus scans available. A free virus scan from a reputable company is a good first step. Whether your machine is infected or not, you need Internet security software. While it seems you like McAfee, we recommend taking a good look at Norton. While more expensive, its new security suite is amazing.

In general, it's not difficult to install Internet security software. While it's been a while since we installed McAfee, we remember the process being pretty simple: go to the site, enter your billing info, download the program. McAfee has its own installer. You should be fine just following the on-screen prompts. Then, make sure the first thing you do is update your virus definitions and run a full system scan (which should be automatic).

As we mentioned above, McAfee requires that you enter your credit card and other personal info before you start the download. If you're concerned that you have a virus that may steal your credit card info, you may want to purchase and download McAfee from a computer you know to be safe and virus-free, and then copy the McAfee download file to your infected machine for installation (use a new CD, just to be safe). In fact, if your machine is infected, it's best to keep it disconnected from the Internet as much as possible. If you don't have access to a clean, trusted computer, consider downloading Kaspersky's Internet security suite; it does not require your credit card info for your initial installation. It also scored better in AV-Comparatives' 2009 Malware Removal test than McAfee did.

NextAdvisor does not have tech support. Since we're a product review site, we don't actually provide the software we review. McAfee does offer some tech support, but it's largely a collection of help documents. Both McAfee and Norton offer "expert" or "guided" installation, but it will cost you around $130 (depending on the product).

Q: Does either the AVG Free Antivirus program or the Avira Free edition have firewalls?

A: According to both websites, they do not. AVG Free Antivirus and Avira Free are anti-virus products, but are not meant to provide additional firewall protection beyond what Windows provides. They also seem to lack some more robust anti-malware and anti-spam solutions (again, we haven't reviewed these products, we're going off the online literature).  The security suites we reviewed do have firewalls as well as other features designed to protect your computer. For more information on those, please see our Internet security software comparisons and reviews.

Q: If windows is 64 bit, does antivirus software have to be 64 bit also?

A: That is a very good question. According to Microsoft, the answer is: yes. Anti-virus software in particular requires specific compatibility. The good news is that most Internet security software we've reviewed are compatible with 32- and 64-bit versions of Windows Vista and Windows 7 (Webroot has yet to make its software Windows 7 compatible). Things get more complicated if you have an older system like XP. Many products are not compatible with the 64-bit versions.

Windows has so many variations in versions and service packs that we recommend that you check the vendor's website to make sure that your system is compatible with the Internet security service you plan on purchasing.

Q: How can you tell if it is safe to download antivirus software?

A: Funny you should mention this. I was just reading an article on PC World about a new piece of scareware that uses a fake endorsement on a real Microsoft site to entice users into installing fake antivirus software. The faux endorsement is part of the scareware's nasty bag of tricks. Installing the software just invites more problems.

With news like that, it's hard not to be skeptical about antivirus software. Scareware is everywhere, and it's doing an increasingly good job of looking like the real deal. The best way to protect yourself from bogus antivirus products is to do your homework, and always download from a reliable source. Make sure that the product comes from a well-known, respectable company. Check out our Internet security software reviews and comparison chart; the links go to the sites of vendors we recommend.

Q: Do you know anything about an online product called Registery Booster by Microsoft?  You can download it for 30 dollars to help clean up your computer. Is it also a security software?  Thanks for you help.

A: RegistryBooster is a program by UniBlue and it is designed to clean up and repair your Windows registry. We don't have any experience with that software,  but  it claims to speed up your computer by getting rid of data fragments that can bog down your computer. It's more like spring cleaning for your computer, but it It will not protect it from malware, spyware, viruses, or other attacks. For that you will need dedicated Internet security software.

What happens if my files are corrupted on my home computer and then they are backed up? Will the backup also be corrupted?

A: It depends on when your files became corrupted, when they were last backed up, and what kind of backup history your online backup provider maintains. Your online backup software will back up your data as-is, preserving any file corruption (just as it would preserve a deleted sentence in a Word document). Now, if you backed up on Saturday, and the files were corrupted on Sunday, you could simply restore the files from Saturday's backup. But what if your backup ran after the files became corrupted? What if your service backs up a file any time it's changed?

There's hope. Most online backup services such as Carbonite, SugarSync, Mozy, and IDrive offer "versioning" (sometimes called "history" or "time-line restore") meaning they save copies of different versions that you've backed up, essentially allowing you to go back in time. Here's how Carbonite works:

Carbonite will save one version for each of the previous seven days, one version for each of the prior three weeks, and one version for each of the prior two months.

So, it's possible you may be able to access older, uncorrupted versions of your files. The amount of time older files are kept depends on your service (Mozy, for instance, keeps 30-days worth, while Carbonite keeps three-months worth, and IDrive keeps the last 30 versions). You should check the individual help section of your service provider for details.

Also note that if the corruption occurred because of a virus, you should make sure you're running Internet security software and that your virus definitions are up to date. Do this before you restore your files, so you don't risk re-corrupting your backups.

I need to download new antivirus protection and I am wondering why you do not include VIPRE in your reviews. Is it because it doesn't work as advertised? Just trying to choose the best.

A: We haven't gotten around to reviewing VIPRE yet. While we can't comment on its effectiveness as anti-virus software, it does not seem to have a built-in firewall. While VIPRE has a separate firewall module available for purchase, we tend to prefer products that offer the firewall as part of the full suite. The combined price of the VIPRE anti-virus and the firewall would push the price into the $50.00 range (or more, if you're looking for multiple licenses), putting it in the same price category as many of the suites we reviewed, such as McAfee. Some, such as BitDefender and ZoneAlarm are even cheaper.

Q: Will Norton Internet Security 2010 software work with both the Windows Vista SP2 32 bit and 64 bit systems?

A: Yes, Norton Internet Security 2010 works with both 32- and 64-bit versions of Vista. Here's the official line from the Norton site:

Microsoft Windows Vista® (32-bit and 64-bit) Starter/Home Basic/Home Premium/Business/Ultimate

Norton Internet Security 2010 is our favorite of the current crop of Internet security software. It's been well-received by the press, including an Editor's Choice award from PCMag, and has captured a number of awards, including the AV-Comparatives Advanced+ rating.

You can read our review here, and you can use the coupon code SYM2010NEW to receive a 10% discount if you decide to purchase it.