The only way that it stays on without freezing like that is when I'm in Safe Mode, so I'm assuming it's a virus. But, when in safe mode, I did a virus scan and it came up with nothing.
I know nothing about computers, so I'm not entirely sure. Sorry if I'm being completely obvious.
May be a virus or could be a program your using or that opens in the background and may not under Safe Mode. You got okay specs for whatever programs you got running? A number of factors such as hidden programs like those stupid Casino Games, Pogo.com shit and stuff that run in your background without you seeing it can slow you down.