Alot depends on the area that's damaged. If the burned area is near the memory there maybe a good possibility, its damaged as well. Pure physical damage may only effect the immediate componet only, but in all cases nothing is guarnteed, so take care. Its best simply to move on unless you want to play. Memory, cpus, cards, are best tested on a spare separate mtrbd. or testbed devices. It doesn't pay sometimes to keep "iffy" parts or devices as it may take down newer replacement or just pester its new home, so proceed with caution.
good luck -----Willy
If you fry your motherboard does that necessarily mean that your cpu and ram stick is damaged (or fried as well)?