Tekkit & Vanilla problem. Weird green flashing textures and memory issue?

[ShelbySunshine]

Hey guys.

I've had this problem ever since I had a new hard drive put into my computer a few months ago, but since I want to play Minecraft again I decided to see if the problem was still there - it was. So now I'm going to ask you guys about it.

Basically, when I play for the first moment or so its fine, everything is regular - but from any time on, the textures turn to weird translucent boxes with green flashing patterns and sometimes solid green problems. Now i know the screenshots are with the tekkit pack - but this occurs in vanilla as well but I figured it was a good place to start. Also, lag spikes hard when this happens.

After a little bit of time with the problem, I get a memory error regardless of how much memory is allocated to Minecraft or java itself.

Evidence:

Error message:

Basically I've tried everything. Uninstalling and reinstalling both vanilla minecraft and mods, using a texture pack, removing it, messing with Java, you name it. Nothing fixes it and I can't find anything on it on google. Can anyone help?