My PC heats up a lot and automatically switches off. Recently when it turned off automatically, I restarted my Windows and it got stuck on login screen for about 15 mins and now it happens on every restart. After entering the password too, it gets stuck for around 10 mins.
I tried defragmenting, virus scan, using cCleaner to clean temp files and registry and installing different antivirus. The system restore points are also corrupted. What could be the problem? I am using Windows 8.
I think the key here is that your "PC heats up a lot and automatically switches off". If the heat is what's causing the shutdowns, and it's been happening a lot, then it's likely that you've damaged a component or two. A PC that's hot enough to complain by shutting down is never a good thing.
I would suggest checking the cooling of your PC components before trying anything else. Most PC BIOS' will have a method of checking the temperature of your devices, so it would be worth checking there after an automatic shutdown.
As anecdotal evidence, a colleagues laptop kept overheating, and he now has a dead hard drive with no way of getting to the data - collecting S.M.A.R.T. data from the drive, via the drive manufacturers diagnostic tools, showed a large number of errors due to high temperature.
Yes, you have damaged some of system files or settings.
If its not corrupted-hardware problem then it's probably fault of registry.
1) Try to recover from Backup.
2) Try to boot with Safe Mode. Does it work normally?
3) If nothing helped, there's a good way to recover from all that registry-problems without reinstalling OS, and I've explained it HERE.
