Uhm. What do you mean by "didn't fresh install"? The random shapes and colors is called artifacting. It would be helpful to post the particular BSOD error too. What graphics card do you have, and what do you mean 3 different drivers?
The first problem you described seems to indicate a RAM or HDD issue. The second problem seems like it could GPU or RAM related.
You should do a clean install of Windows 7. If that is out of the question, try this. Run CCleaner and do the Clean and Registry both. You may have to run it more than once until it comesback clean. http://www.piriform.com/CCLEANER
If that alone doesn't do it, unistall the graphic driver again, reboot, and run Driver Sweeper from Safe Mode. Have it remove any remnants of AMD, ATI, and Nvidia graphic drivers it finds. Reboot and install the latest driver for your card and O/S. http://download.cnet.com/Driver-Sweeper/3000-2094_4-752...