The only hope of correcting a problem like this is to collect sufficient information before trying to do anything else, as the true cause of the problem isn't known exactly yet (just a theory based on previous experience).

If you have access to a second computer with the same version of Windows and hasn't had the problem software installed, the speed of solving will increase.
Other factors are whether or not you are able to reinstall Windows, and the cost (in time and effort of reinstalling apps) of doing so.