mid - high 80s is getting warm, but is not too hot or overheating for a graphics card, most will get into 3 figures before problems will really start. I would still say that your problem is either your.
I just read through your first post too about how you uninstalled the drivers. Because you used a driver sweeper and manually deleted registry entries, there is a high chance that your drivers didn't uninstall properly, so any problems that were there in the first place may still be there. CCC has the option to unisnstall old drivers, and it does it perfectly, no need to go here there and everywhere, using software which almost always doesn't work (driver sweepers) to do something that the program developed by the manufacturer of he card and drivers will do in a matter of seconds.
Download CCC + Drivers for your card from here:
https://a248.e.akamai.net/f/674/9206/0/www2.ati.com/drivers/10-12_vista64_win7_64_dd_ccc_ocl.exe
Run it, you will have the option to install drivers, repair or uninstall. Choose the last one, restart. Run it again, this time installing the drivers. Restart, try again.
What are you using to check the temperatures of your card, and what were you using to overclock your card in the first place?