It didn't happen until I started using 1.7.4 and I know it isn't my computer because I can still run games like Skyrim and Call of Duty with 60 fps.
It loads up in like 5 seconds and freezes the second I click on Multiplayer and if I click it again it goes not responding. I've tried waiting but it stayed on the same screen for 10 minutes until I closed it.
My client isn't modded or anything. It doesn't crash and show a message it just freezes.
And when I opened task manager it shows a couple java things so I think its running still in the background.
I also tried deleting the 1.7.4 in versions folder but now its saying java is still using all the.dll files even when I go into task manager and click end task.
Added (1). Update: I moved the 1.7.4 folder since I couldn't delete it and it downloaded another and it still freezes.