When you buy a brand name computer, there’s a very high chance that it’s come pre-loaded with a ton of “useful” software, utilities, and helper applications. The downside of having all of this stuff at the ready when you fire up that computer for the first time is that it will use up a lot of resources.
One easy way to free up some resources—and hopefully gain back a bit of speed—is to go through your Add/Remove Programs list and remove any software you know that you’re not ever going to use. I also generally suggest using the Microsoft configuration utility (Go to the Start menu, click on Run, and type in ‘msconfig’). From msconfig, you can go to the Startup menu and see all of the things that are loading up on your computer every time you boot up.
There are probably a number of helper applications that you can disable (just uncheck the check box beside something to prevent it from loading at startup). That would include things like the iTunes or Quicktime helper applications, trackpad utilities and any other things like that that you’re not going to use.
Another thing worth mentioning is that anti-virus and firewall software can often take a big chunk out of your system resources, especially some of the big commercial security software that tries to do a trillion different tasks (like Norton, McAfee or ZoneAlarm). You can often use a much less of your system resources by disabling these and running something a bit more lean (like Nod32.
Free and effective Anti-Virus and Firewall programs can be found here: http://www.kevinsprograms.net.