I have an old Nvidia 9800GT that died a while ago, and I've decided to try and resurrect it just so I have a backup card in-case my current card dies on me (which it looks like it is already doing).
When the card died, it basically looked like this with an assortment of other patterns. So I opened it up and left it in a pool of 99% Isopropyl overnight.
After removing the old compound, I applied a (very small) pea sized amount and closed it up. The chip itself is quite small, so I did not put a normal-desktop-sized pea of compound. The card is working normal. It booted with the same issue, but updating the graphics drivers fixed that.
However, the card is running at a higher than normal temperature. The normal for the 9800GT is 60 for idle and 80 for load. My card is running at 78 when the load is 0% according to GPUz.
I know there is some residue of the old compound around the chip, but I'm having trouble cleaning it off. The fan itself is not that good, but I know when the card worked that you couldn't hear it when not under load, but now I can hear it (and no, it's not dusty).
TL;DR: Card died, fixed it but it runs too hot now.