I have now a AMD Athlon 64 DualCore 4450e @ 2.3GHz over clocked to 2.75GHz but if i try to OC it even more then the computer woant start...so how cani OC it even more?

Have new cooler so that aint the problem...

----------------------------

Or where can I find a users manual for the mobo? -can't find it on abits site...

Or is there a limit on the CPU or something like that? (settings now, 280 and multipler x10)

After many months:
in the Advanced Bios features-CPU features section of the bios, make sure that C1E is disabled, and EIST is set to Auto. Use the uGURU utility to set the CPU clock and the memory frequency to the best stable levels for your hardware...

This is for my Abit Intel chipset. Your AMD chipset might be different

can't do anything ith uguru :/ (screen shot taken)
so ho/hat to do..?

Try using the uGuru control utility in the bios...

where in the bios can i find it..?

Mine shows up at the top left side of the opening bios page. But I also have a functional uGuru utility in Windows. You do not. Your motherboard might not support uGuru

yep...not supported
so what to do...when i oc it to 10x280 it first works just fine and then freezes... :/
and how much can I change the voltages? -and will it make a big difference?

Raise the memory voltage a couple of notches and then raise the CPU clock until the Computer fails to boot. Lower the CPU clock one notch at a time until the computer boot and runs normally