Skype Causing Games To Crash And Forcing Reboot?

ever since upgrading my gpu from a hd4870 to an 6870 a year ago i've been plagued with problems of skype crashing my games and sometimes my entire pc. its gotten a bit better since i updated everything i possibly could but it's still a major annoyance that i can't seem to fix no matter how much i try to troubleshoot it on my own.skype runs fine all by itself, zero problems there. however, when you start up a game (any game, its has no prejudices towards any particular one) it will eventually crash, causing the game to crash along with it and force a reboot since the entire desktop will be bugged out with graphic glitches. anything open during the crash will also crash and burn, like web browsers, and they can't be opened again until the pc is rebooted.

so far i've had crashes on diablo iii, minecraft (bsod that actually ruined a world since i was running a hamachi server), left4dead 1 and 2, and most recently borderlands.i also used to get hard freezes when watching Internet videos, but that stopped occurring once i disabled all hardware acceleration in adobe flash. i've looked into the event log and saw a bunch of errors but its all along the line of "skype stopped working" and doesn't seem to really give any pertinent info as to why it crashed my system.also, this never happened with my older gpu but i'm reluctant to put it back in due to how much faster the 6870 is. i've gotten to the point where i'm tempted to buy a 7000 series card but am afraid it won't actually fix the problem.