Think my graphics card has gone bad?

Ok, so during my gaming sessions,i sometimes(very often in the last couple of weeks) get the message that my display drivers have stopped responding and recovered or i get a blue screen. Also,yesterday something else happened , the screen just froze and it stayed like that until i restarted the pc manually. So,these are the tests i've done so far, memtest came out clean , i waited for 3 passes....I've been monitoring my temps and my graphics card is not over 53-55 when gaming.My cpu on the other hand i've been a little worried about, idle temp for the cores is 30 something to forty something... I've done a cpu stress test but i got worried when i saw the temperature going to 68 and i didnt let it go on.
I did a gpu stress test and everytime i get the same things as i do while gaming. Either there's a ''graphics driver stopped responding'' message , a blue screen, or a frozen screen. So,here are my system specs:
OS: Windows 7 service pack 1 / 64 bit
cpu:intel i5-3570
gpu: amd radeon 7850 (gigabyte)
mobo: gigabyte p75-d3
psu: cooler master 600w
The blue screen always has a 0xa0000001 code. I've been using bsod viewer and it seems to be blaming the atikmdag.sys driver.
Also,i forgot to add,i've installed and reinstalled 6-7 different amd drivers for my card and nothing has helped.