I'd guess you're talking about sysedit.exe which provides a convenient way of editing a number of system files, the one you're probably looking for being win.ini - That said, I wouldn't go editing those files, just drop any programs you want to start with Windows in the Startup folder...
Okay, well - go to Add/Remove programs in Control Panel and get rid of any s**t you see there that you're not using, then boot the PC in Safe Mode and run Adaware to get rid of any spyware and stuff that may be on your system.
Cleaning your PC up and getting back some processing power can be a long winded job, whereabouts are ya?