My friend asked me to install an HD7870 into his system. I told him that we'd have to up his power supply from what he had to something a little more capable. He initially got his computer from a prebuilt, it was a matter of getting a new case and PSU (his first one was all mATX, case, mobo, psu was all mATX). Last week we were able to get it fully running for 10 minutes until the PSU shorted on us (upped to a Corsair CX500, 500 watt from a coolermaster PSU, couldn't handle the load). While it was on we uninstalled old drivers, installed included drivers, did a benchmark and Borderlands 2. We did an RMA on the PSU and was able to get a new one on Monday.
I've been booting it and powering it down now all night, nothing. I got it to work once with the on board video and only one stick of RAM, but he was away and I didn't have his password, so I was able to properly turn it on and shut it down twice now. The card and PSU are good, I've tested them in my rig and no problems what so ever.
I've followed [http://www.tomshardware.com/forum/261145-31-perform-ste...] all the way down to the bottom and I've reset the CMOS about five times now hoping to get to the windows log on screen again to do a clean reinstall of the video drivers. Last night I even put an old card from one of my older builds into his, nothing. I've used about 2 monitors now as well. If it helps any, when I can get it booted up, I sometimes have to hold the power button for 5 seconds before a proper response. All front panel pins are okay.
Intel Core i5 LGA 1155, stock cooler
As I said, not exact about motherboard because I didn't build it initially, all I can read from it is ASUS ESD TurboV. UEFI bios.
It's all ASUS brand, RAM included, 3 sticks of 4GB RAM
ASUS Radeon HD 7850, I've been swapping it out with a Sapphire Radeon HD 7770 from my rig. Initially it had a Nvida GT520.
Corsair CX500 PSU 500 watts
1 hard drive, 72000 RPM 3.5mm, Western Digital
Coolermaster HAF 912, he added his own fan in the front
When I boot, I always unplug the mouse and keyboard, I don't think it's a power problem but I'd like to make sure it's running as pure as possible.
Steps taken to resolve:
1. Checked front panel cables, checked PSU cables
2. Removed CD drive
3. Added CD drive, removed card, was able to boot to bios and eventually log on screen
4. Disabled on board, added card again
5. No joy, removed card and PSU, installed into my rig, no problems
6. Ran without card, no joy
7. Ran with only one stick of RAM, no joy
8. Followed shortstuff_mt's 'Guide to no video/no boot' in full
9. CMOS reset
10. Booted twice properly, no password so I had no access any further than log on screen.
11. Waited for friend to provide password
12. Failed boots, fan and lights working but no joy
13. CMOS reset
14. Nothing, fan and lights, but no video