Did you upgrade to bios 484 BEFORE you inserted the Q9550S? If not, put the X3360 back in, upgrade the bios, then insert the Q9550S.
BIOS was the latest one, 500 & something.
BTW; after putting Q9550S (which did work, just the WIN10 wouldn't load)...then I've restarted & got this black screen with white underline that's permanently on (not blinking).
Tried to put X3360 & E6550 on motherboard, same thing.
Now removed the jumper to write the BIOS again...it stalled on step 29, according to PC Analyser. :/
Correction, stalled on same step EB...black screen with white underline is ON.
Processor is E6550 inside.