Before now my computer worked (relatively) fine, but when I started it up this morning, it took 10-15 minutes to start after the Microsoft Inc loading screen, which also took longer than it normally does (2-3 times longer). The only thing that I can think of that's different is that I temporarily changed my settings from looks to performance to reduce gaming lag. After changing it back, windows explorer also crashed, if that means anything.

Does anyone have any way to fix this without spending a million dollars at a computer store? Shutdown also takes way longer than it should, as does opening certain programs like word and notepad.