How can I tell if my mb died

Some boards have a power led on the board. But I always do a bare post on a non conductive surface when installing a new board or troubleshooting. This may be your last effort before you rma the board. Always try an rma if your board is within 3 years old; the worst they can say is no.

Your motherboard may not support your new processor. Or it might need a bios update to run it. Just because it fits in the socket does not mean it will work.

List your motherboard and new processor so we can tell if they are compatable first.

http://www.asrock.com/mb/overview.asp?Model=K10N78FullH... the cpu's i have used and had it working with are the athlon 620 and the phenom II955, i know compatibility isnt an issue as the boards bios was up to date and also i have used the cpu's in the motherboards in both cases with success, since yesterday though nadda.