Shorted Motherboard

Hi:

I hope i'm in the right forum, if not, please forgive me. Last week I forgot my computer was on and I attempted to connect power to my hard drive. It sparked and system shut off. When I tried to restart it the fan on the motherboard started and then immediately shut down. I took the battery out for about an hour and replaced it then the system started fine and booted up. However, the hard drive runs very slow now almost there is not enough memory. Thinking I may have damaged the hard drive, I put in a new hard drive and the result is still the same. Does anyone know what may be going on? Here are the specs:
Motherboard - Microstar 6309
Memory - 1 gb (registers in system)
Pentium III 800Mz
40 gb hard drive

Thanks for any help.

Eric