After reloading the image, if you still have the same problem, can you create a new 'test' user account and see if the comp loads slowly? I've had a problem with a corrupted user account file and needed to make a new one. It was a quick resolution. Might be worth a shot.
If it loads fine, then you could move your stuff over to your new account. Presuming you are using XP:http://support.microsoft.com/kb/811151
If you're still running into probs, like Budapest said, you might want to reinstall the OS to make sure all the system files are free of corruption.
Edited by jhsmurray, 24 July 2007 - 03:12 AM.