Here's my experience with reflowing a GPU AKA baking it.
I just got this artifacting XFX 8800GT Alphadog Edition (go ahead click it)
It had corrupted text from boot, red blocky lines in windows and sometimes squiggly red lines. It was basically dying
What I did was take it apart, clean it thoroughly, bake it 10 minutes at 200° C, let it cool 60 minutes, change thermal paste and put it back together. This is a known problem in this generation of cards (geforce 8), my t61p thinkpad also died of bad BGA soldering (G86). But fortunately and surprisingly some can be brought back to life for an indefinite amount of time. Here are the pictures (the first is actually after the whole ordeal for reference). The fan is incredibly loud, and the card itself isn't much faster than the intel HD4600 so I won't be using this in my PC. Still it has been a fun and nonconventional fixing experience: