I ran into a problem today when I bought a computer from some guy for a fairly cheap price. IT had a 680w power supply and a decent processor older board and 4gb of ram. No my problem is when I turn on my computer my monitor will sometimes not turn on which would be caused by a no signal from the computer. Now when it does happen to turn on it happens to freeze at random times. Now the POWER SUPPLY is making a quite loud HISSING noise. Which everything turns on motherboard graphics card cpu etc etc. I was wondering if this could still be the problem for the no signal to occur. Also when I actually get all the way to windows I installed my wireless adapter and it would tell me to restart. When I restarted it, it would get stuck at the shutdown screen. When I reset the computer I would go see if the wireless is working and when I would click on the wirless bars in the bottom right it would instantly say not responding and freeze and not connect. Something fishy is going on. Not sure what.