The problem started last night when all of a sudden the PC restarted itself. Now everything seemed fine as its was booting.... Then Windows splash screen appears and then the desktop shows up.

Now that's where the problem starts. It just hangs at the desktop. I can't click anything or do anything for that matter.

I've tried using Last Known Good configuration but it didn't help. However i can run in safe mode.
I haven't installed any software or made any driver changes of late.
I also tried opening and cleaning the PC hoping that the problem might be dust related but even that didn't help.

I've had the PC for about 1year now so I doubt that my devices are worn out.

I really don't want to have to reformat. I know many have faced the same problem in the past. I really need your help. I completely depend on my PC for school work.