Programs that startup when your computer boots can drain your computer's memory.  There are 3 web sites you can use to help determine whether these startup programs are necessary.  Answersthatwork is my favorite listing.  Three alternative sites are located at Windowsstartup, Systemlookup, and Sysinfo.  

Windows Vista comes in 32 bit and 64 bit versions.  This web site will tell you how to determine which version is running on your computer.  In Windows 7 click the start button, then control panel, then system and maintenance and then system.

 

This website provides instructions for determining how much memory your computer needs, since some users require more memory than others.

There are many different types of memory that are used by computers.  It is imperative that you purchase the proper type.  Crucial, a manufacturer of memory chips, has a small free program on its site that will determine the type of memory your computer uses.  Other chip manufacturers have similar programs as well.

 

PC World wrote an article that contains many additional tips for speeding up and maintaining your computer.

Security holes are periodically discovered in both Windows and other programs that run on your computer.  New software versions are released that close these security holes.  You can use the web site Secunia which will perform a free scan of your computer and tell you whether the software you are using has any known security holes in it.

Symantec Norton Antivirus 2009 as well as other programs released by Symantec sometimes prevent you from using Windows restore points.  There is a workaround to this problem which is described in this bulletin.  A similar verison is available for Norton 2010.

If you wish to determine the connection speed that your ISP is delivering to your house, visit the Speakeasy website which will perform a free speed test for you.

McAfee Siteadvisor can help you avoid dangerous web sites by alerting you that the site you are about to visit may contain harmful viruses or spyware.  They offer a free download that works with your browser to provide you with these warnings.