Why does my PC keep crashing(Blue-Screen)?

[787]

Alright, so lately I have been having loads of trouble with my PC. I would say for about a week now, it has been randomly blue screen crashing at least once a day, and in order to turn it back on I have to unplug the tower and wait about a minute, then plug it back in. It's getting really frustrating, as I have then had to wait for it to turn back on (which lately has been taking far longer than normal), and then resume whatever I was doing.

Hardware of my PC(Detected with ma-config):

Processor
AMD Athlon 7750 clocked at 2.70 GHz

Motherboard
Gateway RS780 Rev 1.0

Memory
4 GB total memory type DDR2

Graphics card
ATI Radeon HD 3200 Graphics
Radeon HD 4350

Harddrive
Harddrive WDCWD2500KS-00MJB0 from 232.89 GB SATA II


Programs I was running at the time of the latest crash:

2 Instances of Hitleap Viewer 2.8 (Traffic Exchange)
Dogecoin-qt (doge wallet)
Bitcoin-qt (btc wallet)

Google Chrome
Tabs:
-Bitcoinplus browser based bitcoin miner
-Bitcointalk forum
-Freebitco.in

I know, it seems like I am REALLY addicted to bitcoins. Trust me, this is just an odd coincidence that I had so many bitcoin related things open at the time.

So anyway, the last time it crashed (about 30 minutes ago), was when I got on my PC this morning. I did the capatcha on freebitco.in and was about to check the forum when it went to a black screen with some random flashing lines at the top of the screen and then blue-screen crashed.

Any help is greatly appreciated. Sorry if I gave unnecessary information or didn't give the right information.
My case is currently open, I've had it open for a couple of weeks now to increase circulation.
I have MSI afterburner to watch the temp of my hardware, etc. and since I opened the case the GPU and things haven't been increasing much at all in temp. My PC was sold to me for gaming, which is why I would have 2 graphic cards. Or at least I am pretty sure it's two different cards.

The next time it happens (hopefully it doesn't, but you know, it probably will), I will check the blue screen message. Thanks to everyone's responses.