i just upgraded my mobo cpu and ram, and had no problesm with it, didn't even uninstall the previous stuff relied on windows 7 to sort itself out. Purists would say reinstall windows though
Also, I've had problems with misdiagnosing faulty parts before. A solid motherboard really helps save time and money (it can cost a fair bob in RMA'ing goods, some companies will pay your p&p, but others won't).
In my recent upgrade where I got a brand new mobo and brand new ram and used CPU, my system didn't get into post. I thought "heck I just bought a fault CPU", was about to send an email to the seller, and then I picked up the motherboard manual and had a read.
This is a good mobo and has fault lights for each components, ram, cpu, gfx and a few others.
RAM lights went on so I had a look turned out that one of the rams didn't quick sit in place properly, so I reinserted it and it worked fine.
You don't get that with ****** ASrock boards, so when the systems fails you have no clue which part it could be, and if you don't have spare parts to test with you end up purchasing all sorts of different replacement parts you don't need.