Maybe my moatherboard is damaged?

Hello, I recently droped my computer while moving it around, it has lately been acting very very wierd, it normaly took about a few mins to boot up my computer in VISTA, now it takes like 30 mins at least, when inside VISTA it lags alot, it's hard to even write in it, writing this is a pain. and every now and then it comes up says "memory dump" and goes into a blue screen and reboots itself, so i get the pain to reboot again and again. I've checked my RAM and replaced it with some newer ram didn't help a thing. can it be the motherboard that have been damaged? is there any good way to check it ? without replacing the motherboard? my computer aren't super good, so i wont invenst too many money on repairing it. thought i would try to hear first if anything can be done before i decide to buy a new one, i would deffently love to save the money for another time

my system spec is:

Intel Due 2 E7300 @ 2.66GHz
Kingston HyperX 2 x 1 GB
Gigabyte X38-DS4
gforce GTS 8800 512 MB

Thanks