So my main rig (watercooled) had been running stable for years, then the other night in an effort bleed the last of the air out it I had it turned upside down and switched on. THis got the air out but when I had it upright again and all hooked up I no video and the board error code (98) suggested no video. My immediate thought was that water must have leaked and fried the video card (Radeon R9 290) although there was no evidence of this. When I plugged the video cable into the onboard graphics the PC booted straight away.
Anyways I took the card out and swapped the waterblock off it for the air cooler and just to check I put it in another rig, and it booted fine!! So I put a spare video card in the main watercooled rig and it boots as well but put the 290 back in (now aircooled) and I get the same error code and no boot. Tried different psu and cables still wont boot. I'm at a loss as to what the problem is so has anyone got an idea??? The motherboard is a Gigabyte Z77X-ud5h by the way.