There's a couple bad things that can happen while OC'ing. Since I don't believe you bothered to look them up, here it is:
While just upping the FSB, here's a few bad things:
1. The increased FSB can sometimes cause data corruption on your HDD if the other clocks aren't locked.
2. You can up the PCI bus frequency if the clocks are synced to the FSB, which is bad (might fry your video card).
3. Your RAM is running at a frequency that it can no longer handle, so it does not POST. This is really no big deal, but you have to reset the BIOS and start your over clock all over again.
4. Your CPU runs at a frequency that it can no longer handle, and does not POST. Same as the RAM, just reset the BIOS.
5. Your CPU gets too hot which may cause further problems. This probably won't happen unless you have terrible cooling, as simply upping the FSB usually doesn't alter the temps too much.
If you screw with the voltages too, you CAN permanently damage your CPU, or completely fry it. I think 1.8 is the drop-dead zone for AMD A64 chips, but almost all chips are around that (look it up to be sure).
Seriously, if you want a good over clock where nothing goes wrong, research first. Then research some more. Then when you think you know what you're doing, read some more.
