Witcher 3 The Wild Hunt

Yesterday while playing witcher 3 for like a few mins i encountered a weird graphical like this http://prntscr.com/mvshrs I restarted the game n it was fine but it appeared again in a few minutes. Then i used DDU to reinstall the SAME driver and then it stopped Is this perhaps a sign of a...

I have a really old computer on which I installed windows 7 (the good old XP is not even supported by some softwares anymore). What I didn't know when I installed Windows 7, is that there are no Windows 7 drivers for the graphic card (the one i mentioned in the title). So I found out that...