Custom pc not getting a video signal

hello all, i am new to the forum and just stumbled upon it looking for answers to my problem. i have a new pc i built that has had a lot of issues from the start, had a couple DOA boards from MSI and finally got one to work, it had been working for about 4 months then one day while i was messing around in ableton live 8 (music software) it just completely shut off and i was pretty sure i could smell something burn. there was no loud pop or anything it all just quietly shut off. i couldn't tell what part specifically smelt burned but i could not get a video signal afterwards so my first thought was graphics card or motherboard. Everything powered on as it normally does so i started by swapping cables and monitors just in case, then i tried my motherboard graphics and got the same no video result, i tried a brand new PSU and nothing, got a brand new motherboard without on board video from Asus and still getting the same problem. I am fairly new to building computers so i know there are other things to try, i have a friend that is really good with computers thats also been helping and he wants to try his CPU on my build and then his graphics card. other than that is there any input you guys have on this issue?

processor- AMD 965 black edition quad core
graphics- MSI 560 TI hawk edition
PSU- 850w thermaltake

If you need more info on my system i can give u specifics when i get back from work and can look.

thanks in advance for any help