Very weird problem I cannot figure out

Happens to me 1-2 times in a month and it's very annoying.
As i'm playing my interface gets bugged i close the game and when i doubleclick the exe again it starts downloading instalation and overwrites the existing dat file. I cannot fix it and the only way seems to be reinstall which is a lot of downloading even with the instalation cds.

It sounds like when it crashes, it corrupts the gw.dat file, and the game see the damage and it then re-install it.

I would use the -image command to make sure you have the entire game downloaded and verify it's working. I would back up the gw.dat file once a month.

It could be hardware or software related... I would use this program http://www.memtest.org/ and have it check your memory for physical errors.

I agree with EternalTempest. This sounds like a RAM problem to me, but could also be a hard drive problem. I've also seen bad IDE drivers do things like this. I'd start out with Memtest86+ as ET suggested and go from there.

Backing up your Gw.dat file won't fix the problem but it's probably the best solution until you figure out what the problem is and fix it.