Thanks for replying. I have indeed tried that but no result. Though if that Z77 is older than my motherboard then I still have hopes to make it work somehow.Try a cmos reset then install the AMD card. My old Z77 Extreme 4 would not post if you changed the GPU and didn't do a CMOS reset. IIRC my P67 Extreme 4 was the same way.
I have options like boot option: Legacy-UEFI. and another one making me pick between legacy or uefi OpRomModern graphics cards require a UEFI bios to be detected.
Your GA-H61MS2P was launched about the time legacy bios was transitioning to UEFI
Legacy bios is monochrome and text oriented.
UEFI is in color and looks like a web page.
You may have some sort of an option in the bios to handle a UEFI card.
If your bios is not current, see if an update is available that looks like it might fix your issue.