Centralize all of your program and application CDs and while you’re doing that, get rid of the obsolete never-used-once software disks.
If you only use WebMail, download a copy of your emails with an email client (Outlook, Thunderbird, Apple Mail, Windows Live Mail). This way, you can backup your emails locally in case Google, temporarily, loses half-a-million email accounts, again.
Remove pesky dust bunnies lodged on your tower vents (desktops). The safest method is to turn off your computer, disconnect the power cord, then use compressed air. Wait 5 minutes before turning on your equipment.
Wipe the monitor screen with a lint-free dry cloth or chamois if there are no fingerprint smudges on it. If there are smudges, use a lint-free cloth damp with plain tap water to clean it. Turn off your monitor screen before wiping it clean.
Clean your mouse and keyboard too, and use compressed air to get rid of any particles lodged between the keys.
Do you own a domain name? Do you have a website? Make sure your domain is registered under your name. Please, do not respond to email and snail mail solicitations for domain renewal. Always contact your domain register or web hosting company.