Secure your PC with a password
Always a good first step, protect yourself from unwelcomed people.
Keep Windows up to date by installing all updates
Whenever Microsoft detects a security flaw in windows, Microsoft always releases security patches to fix vulnerabilities.
Install Security Software: Anti-Virus, Anti-Spyware, Firewall, Spam Blocker, Anti-Malware
Even though you might think an anti-virus is enough, it is not. There is a slew of threats that anti-virus are not made to detect. Always install extra security. If you don’t want to spend money, do not fret, there are plenty free security software available.
Keep all security programs up to date
This includes antivirus, firewall, and antispyware programs. Set them to automatically update.
Scan your PC
Scan your pc for viruses, Trojans, worms, spyware, and malware at least once a week. If one virus gets through it can open the floodgates for more and make you computer not usable. The earlier you neutralize the threats the better your pc will work.
Back up your valuable information regularly
If you can, buy an external hard drive to keep your vital information in case of computer failure.
Partition your Hard Drive
If possible seperate your HD into two partitions. Make C: for windows, and D: or E: for downloads, video, photos, and everything else. Once you install windows don't touch the C drive. Most
blue screens of death occur because people mess around with important windows and regestry files.
Switch from Internet Explorer
Internet explorer is subjected to the largest number of security threats. Try a different browser, Firefox, Opera, or Google Chrome.
Be careful when downloading
Be careful when downloading from unknown sources, especially when downloading peer to peer. Try to abstain from downloading torrents and from programs like limewire due to risk of viruses and its most of the time illegal. If you do download always scan the download for infections right away. Try to download from safe sources like download.com.