OK, what files?
Try this. Give your computer the three finger salute (
Ctrl + Alt + Delete) to open
Task Manager. Click the
Applications tab, look at what programs are running. If you didn't start them, then they are aither still checked in the
System Configuration Utility (
msconfig), or the program has an option somewhere in it that tells it to start up with Windows. If you have unchecked it but it returns, open it up and look for this option, then uncheck it.
As for other things you can do...
Uninstall any old programs you don't use. Go into your C: drive and delete the folder left behind, if any. Then go to MajorGeeks.com and download TweakNow (
http://www.majorgeeks.com/download4134.html). Run it. Tell it to delete everything that it says can be safely delete. Leave everything that it says can't be deleted safely. Look at the ones it is unsure about. If the entry belongs to an uninstalled application, chuck it.
After you have cleaned out the old, click
Start, All Programs, Accessories, System Tools, Disk Cleanup. Let it find what it can, then check the entries and let it clean them out.
Now, since you have taken care of some housecleaning and nixing old unused space hogs, you need to defrag your hard drive. Before you start, turn off your screen saver and every other running program (besides Windows)...use the Task Manager to be sure. Click
Start All Programs, Accessories, System Tools, Disk Defragmentor. Have it
Analyze your hard drive so it can tell you if it needs to be defragged (probably will though). Then tell it to
Defragment your hard drive.
How much RAM (memory) does your computer have? If you don't have enough, your computer can bog down really easily.