Hard disk wont get detected

Dear All,
I have the following problem .
The clock on my pc was showing a wrong time.I changed the Motherboard cell .Later when the computer worked ok for a couple of times ,the time was showing right.But than when the I started the PC after a day the screen was garbled ,icons garbled the start menu disappeared. Was getting an error message that I need to install a file gdplus.dll something.I got my windows boot cd and tried to get into recovery console but it kept saying that my administrator password was wrong ??? Odd.
I tried reinstalling the OS, It did reinstall but the screen never shows up I just see a mouse cursor.Next I tried connecting other hard disks I have none were detected ,now no hard disk is detected???.I changed the IDE cable connection slot.Nothing seem to work no hard disk is detected.I even put back my old CMOS CELL nope doesnt work.Tried Booting into knoppix ,didnt work.Had tried safe mode before didnt work.What now.
Do advise.

Board = GA-7VAX
AMD PROCESSOR
WINDOWS XP HOME
IDE