What is making my computer run so slow some days?

Some days it is fine, but then other days it takes forever to load a page. I have done all the disk cleanups and defragmenting. I have an antivirus running. I have done the ctrl+alt+del, but not showing anything that would be running in the background other than the pages I am viewing. Is there anything else that I can do to speed it up.. preferrably for free.

And please put the answers in layman's terms... I am a little computer illerate at times..

Thanks for your answers in advance.

What is making my computer run so slow some days?best antivirus software

There are tons of things that can be done to help speed up your computer

First disable any unnecessary programs from starting when you start windows

Start%26gt;Run%26gt;type in MSCONFIG%26gt;Startup tab - uncheck any program you don't want to run when you start Windows

For more info see the links below

Streamline your startups

http://www.pacs-portal.co.uk/startup_ind...

http://www.answersthatwork.com/Tasklist_...

http://www.windowsstartup.com/wso/index....

http://www.3feetunder.com/krick/startup/...

http://www.greatis.com/appdata/

http://www.castlecops.com/StartupList.ht...

Then disable unnecessary services

Disable Unneeded Services In Windows XP

http://www.blackviper.com/WinXP/servicec...