Hi, assuming you have not made any recent changes, perhaps all you need to do is a little bit of 'housework'. I would suggest, in this order - in IE got to Tools>InternetOptions>Temp InternetFiles, then delete Cookies and Files.
Next - right-click on desktop and hover over Arrange Icons by, but then go to Run Desktop Cleanup Wizard. Next - do a full virus check with whatever virus prog you use; then do the same with Ad-Aware SE Pers (click here).
Next -Go to Start>AllPrograms>Accessories>SystemTools> and do a DiskCleanup ..... then via same route do a Disk Defrag. Restart after all this and hopefully your general Startup should be quicker.