GW freezes and not able to play

Okay, this is now getting on my nerves...
When I first bought GW I had no single problem with it, but then I got bored and removed GW from my CPU. Now, a month ago I was going to try GW again and I love it again. (Reason why I stopped was because I had only 256RAM, now I have 768RAM)

So, the game freezes and I get the "Report Crash Screen" and I submit it, and then a Ctrl + Alt + Del helps, but when I want to start GW again, I get this error:

http://img523.imageshack.us/my.php?image=gw6sh.jpg
Specs: P4 - 2,40 Ghz - 768 RAM - Geforce MX4
I have to reboot my computer to play GW again... And this happens maybe 2 or 3 times a week...

But, here comes to other serious problem: Everytime when I play GW, I sometimes get weird flickerings on my screen, like my screen goes black for a couple of miniseconds, it's like lightning flashes/flickerings on my screen...
I thought this was something to do with overheating, because sometimes I get weird textures... The flickering happens almost every time when I open my Inventory, then sometimes my Character Outfit becomes White-Silver-Grey and the screen won't stop flashing after a couple of seconds...


I hope this has something to do with GW, because if something is overheating, I can't afford to buy a new piece of hardware right now... And I don't have other problems in other games...