Video Driver issues with my custom build

[steviedoors]

I built my PC at the start of September, and it was fine for a while (maybe a month or two?). But eventually the video driver started crashing. My screen would freeze for a second or two, then go black for another second or two, then it would go back to normal, with a little message in the bottom right corner saying the video driver had crashed. This happened maybe once every few days, and continues to(I'm probably exaggerating the frequency of it but it's something like that).
A month or two ago, I started getting problems playing YouTube videos. I seem to recall I struggled to get them to play for a few days, until it went back to normal. But just now, I got a bluescreen (just a few minutes after another crash) saying something about the video driver, then it restarted. So I'm curious as to what the problem is, and how I might fix it?
I have been updating my graphics driver through Steam recently. The graphics card I have is a Radeon HD 7750, and I have Windows 7 x64. I can give more detailed specs if necessary. Thanks.

 

[steviedoors]

Also, another thing (since it won't let me edit for some reason): if I leave the computer in sleep mode for too long, it won't turn on again unless I power it down completely. This started happening maybe a week or two ago.