If you go to the start button on the lower left side of the desktop and left click it, then left click the "run" icon in the menu that pops up, then type "msconfig" in the command line without the quotes, then on the window that opens go to the tab labled "Startup", you can change what programs start every time you start your computer.

My advice would be to click everything off except any antivirus or antispyware programs. If you see lots of entries in the C:\Windows\System32 folder you more than likely have spyware and/or viruses.