Perhaps; however, a virus/malware can hide in something as innoculous as an image file. In today's day and age you can get a virus from anywhere."But, I don't do stupid things or go to sites where I could get infected!"
Here are some common sense steps that you can do to protect yourself from viruses with a very minimal effect on system performance:
1. Install an anti-virus software such as Microsoft Security Essentials (MSE) (http://windows.microsoft.com/en-US/wind ... essentials). MSE is a free light-weight virus scanner that does a pretty good job and does not hog system resources. If you would prefer additional protection, you could use ESET's NOD32, McAfee Antivirus, Kaspersky, or Norton Antivirus. I personally recommend combining MSE with NOD32. Derrick recommends Avast (also free) stating in the 5 years he has used it he has not gotten a virus.
2. Enable Data Execution Prevention (DEP), which is built into modern versions of Windows. DEP prevents programs from being loaded first into memory and then being executed. It is very rare that a program would need to execute from RAM, and if it does its usually up to no good. Many viruses execute from memory to avoid detection. DEP prevents this. Your system may or may not support DEP; however, you can enable software DEP.
To enable DEP, do the following:
Windows Globe -> Control Panel -> System -> Advanced System Settings -> Performance -> Settings -> Turn on DEP for all programs except for those I select (the SECOND radio button).
3. Enable Windows Firewall. There is really no reason to disable Windows Firewall.
To check your Windows Firewall settings:
Windows Globe -> Control Panel -> Windows Firewall
If there is an option for "Use Recommended Settings", click it. If you want to allow a program through, you can find a link on the left that allows you to add exceptions.
Alternatively, you might want to use a full security suite. Unless you really know what you are doing, I would not recommend this; however, ESET Smart Security is a pretty decent package.
4. Enable User Access Control (UAC). UAC is essential in protecting your computer from programs that wish to modify system settings. UAC works by prompting you for whenever the system needs Administrative access (even as an Administrator). Do NOT blindly click "Allow" whenever the system asks you if it can make a change. Make sure that you always check what it is wanting to do!
To verify your UAC settings:
Windows Globe -> Control Panel -> User Accounts -> Change User Access Control Settings -> Notify my only when programs try to make changes to my computer (second notch down)
5. Make sure that Internet Explorer is configured correct even if you do not use it. The Internet Explorer settings affect other software than just IE, so make sure it is set correctly.
To verify IE settings:
Windows Globe -> Control Panel -> Internet Options -> Security -> Internet -> Default -> Local-Intranet -> Default -> Trusted Sites -> Default -> (delete all sites in the list) -> Restricted Sites -> Default -> Privacy -> Default
If; however, you think that you have already been infected by a virus, you might wish to do the following to clean your computer:
1. Run a FULL scan using MSE or whichever virus scanning software you have installed. Make sure that the definitions are up-to-date. If they are not, a scan will be pointless.
2. Install Malwarebytes (http://www.malwarebytes.org/mbam-download.php) and do a full system scan. Malwarebytes is good at finding some viruses and a lot of malware. Make sure that you do NOT install the real-time scanner or the set it and forget it functionality. You just want the on-demand scanner.
3. Install Spybot Search and Destroy (http://www.safer-networking.org/en/mirrors/index.html) and do a scan. Spybot S&D is good at finding rootkits. Make sure that you do NOT install the real-time scanner or the set it and forget it functionality. You just want the on-demand scanner.
4. Repeat steps 1, 2 (scanning), and 3 (scanning) again.
5. Do a Windows system file integrity check using the Windows built-in integrity checking tool:
Windows Globe -> All Programs -> Accessories -> Right-click on Command Prompt and select "Run as Administrator" -> type: sfc /scannow
Following these steps, you can help ensure that your system is better protected against viruses and malware; however, there is no substitute for vigilance. If you are not careful with what you do on the internet, no amount of protection from scanners or Windows' settings will protect you.