Well, if the pc restarts that's deffenately a sign of hardware faliure, (yea i know, i'm captain obvious), but it is by no means due to your vram. IF your vram woulld be deffective, your problems wouldn't present themselves as over-heating. if u still have any waranty left, you should pester the people you bogght it from to either fix it , replace it or give you your money back. I do have a little experience with pestering shops into fixing components for me , but you really really have to bug the living crap out of them , and call them constantly to ask for details and situation updates, because if you don't they will pay no attention to your components.
This summer i sent my mobo and cpu to get fixed twice . The first time i let them do their thing, and they did nothing for me , and the second time , i emaild them and called them constantly , untill they payed attention , and they ended up refunding me more money then i payed for them (cuz i got them on sale).
As a future refference , you should probably shy away from brands like inno3d , there are better brands out there that use better components for cards, like asus, or msi. Personally, i haven't heard a word about inno3d since i bought my geforce 6950 (and that was like 10 years ago).