I recently upgraded from an HD 6900 Series adapter to an R9 390. The card ran great for a few weeks. Then, quite suddenly, my whole computer would power off. Eventually, it would not boot at all. Ultimately, I tried putting the HD 6900 card back in and the system powered on fine. I have a 750 watt PSU. So, I don't think that was a problem. I've tried different PCI slots to no avail.
Here's some info on my system:
Operating System: Windows 7 Home Premium 64-bit (6.1, Build 7601) Service Pack 1 (7601.win7sp1_gdr.160121-1718)
System Manufacturer: Gigabyte Tecohnology Co., Ltd.
System Model: X79-UD3
BIOS: BIOS Date: 11/02/11 13:46:55 Ver: 04.06.04
Processor: Intel(R) Core(TM) i7-3930K CPU @ 3.20GHz (12 CPUs), ~3.2GHz
Memory: 8192MB RAM
Any recommendations on how I can fix the card?