I If you thing your hadrive is giving your Problems, i would set the bus back to default, and scan for errors....
When all erros fixed (if any) run at your overclocked speed again.....
After a while, look for errors in the hardrive again (scandisk or whatever you like better)
If you hardrive doesnt like tha higer PCI speed, not good.... it may be your hardrive after all, more testing needed.
Odds are its your NIC. NIC's have a high rate of craping out when running out of spec.
@ 66 FSB your PCI clock should be 1/2
@ 100, 1/3
@ 133, 1/4
the goal is to have your PCI bus running as close to 33MHz as
SPEC
you can. So 66 x 1/2 = 33.3 = good. 66 x 1/3 = 22 = too slow
Overclocked
75x 1/2 = 37.5, close. 75 x 1/3 = 25, 1/2 is better
Get it?
Most hardware will run fine with a PCI bus of 37.5...
Its the 40's that give most people trouble....
But NIC's are picky.