Patches and Updates
For Microsoft Windows users, make sure to setup your computer for Automatic Updates. Automotic updates will ensure that Windows has all the latest critical security patches and system updates. At least once a month, visit Microsoft's Windows Update and look for optional updates and hardware updates. These other updates for your computer are not automically installed when your computer is configured for Automatic Updates.
Regularly check the manufacturer's website for updates, patches, & new drivers for installed software applications (i.e. word processor, spreadsheet, games, etc.) and peripheral devices (i.e. cameras, external drives, scanners, printers, etc.).
Security
Protect your computer from spyware, adware, viruses, trojan-horses, and other malware by making sure you have up-to-date security software. Security begins with an up-to-date (version within last 18 months) Anti-Virus, Anti-Spyware, Anti-Spam, and Firewall set of applications.
All Internet and email enabled computers are vulnerable to infection from spyware, adware, and malware. Typically, the Anti-Spyware/Anti-Malware protection that is found in Anti-Virus software or Internet security suites is not adequate enough to protect your computer. Anti-Spyware products by Webroot - SpySweeper, Lavasoft - Ad-aware, and Microsoft - Microsoft's Windows Defender provide excellent protection for your computer. Rootkits are one of the greatest threats to today's computers. Effectively, an installed rootkit, may allow malicious software to mask all of it's associated files and folders from Windows and security software. SpySweeper version 4.5 and above detects rootkits and does a good job of removal. The only way to guarantee your computer is free of a malicious rootkit, is to remove the hard drive(s) and scan it from another computer. Once your computer is certified rootkit free, SpySweeper will help prevent a malicious rootkit installation.
Internet security suites by McAfee, Symantec, Trendmicro, Kaspersky, Computer Associates, and Zonelabs secure your computer from spam, viruses, trojan-horses, worms, keyloggers, and more.
Make sure to schedule or run a weekly scan of your computer and keep your software up-to-date. Run your security products for two years (making sure to renew your subscription at the end of the first year). At the end of the second year, upgrade to the latest version to ensure your computer is running the latest security technology.
File, Movie, and Music Sharing
Don't! It's illegal and you're bound to infect your computer.
Look at inexpensive alternatives. MusicMatch, Napster, iTunes, and Real provide subscription based radio and music on demand services. A great product for recording music is Replay-Music.