I have an A7V333 system at home and I unlocked the XP 2200+ CPU I'm using with it.
I've also played a lot with various memory settings, other bios settings, benchmarked at every step, and played with several different BIOS versions (which does make a difference - every BIOS after 1006 is less friendly with an unlocked system).
Please give me some more info on your situation and I'll try to help.
What CPU?
What exactly did you do to unlock it? (Connected across which L1 and/or L3 and/or other bridges, and using what technique?)
The last time it was running, what were your BIOS settings (FSB, 1:1 or 4:5 FSB to Mem, what memory timings, chipset at Turbo or Optimal)?
What BIOS version are you running?
From my experience the "standard" failure due to overclocking or otherwise pushing settings to hard is that the system fails to boot up - speaking or beeping some errors (have your speakers hooked up and powered as the POST reported talks). You then hard power off and back on again, and it dumps you into the BIOS with some default settings and you start over. If that's not happening, you can try a hard BIOS reset using motherboard jumpers (check the manual - I'm not familiar with this), or you've got a real hardware problem. Make sure your CPU fan is plugged into the right header on the mobo (it won't boot otherwise), make sure the memory and CPU and heatsink are all properly seated and all that jazz. Do you have access to any parts for swap tests? You can also try undoing your unlocking mod, but I'd recommend posting more info here and getting some more feedback first.