need help wi a stupid chip

I have 1.1 duron i oced it locked up to 1.38 everything was fine system ran great. But then i unlocked it once and i could only oc up to 1.19 and it would boot up into windows but then it would reboot and give me a bios checksum error (only happened once) fixed that. Then i took the chip out and reunlocked it. Got better results i got up to 1.36. But then after about 20 mins it would reboot and do a system checkand it did this about four time at 10.5,10.0,11.5,11.0 multi.

What could the issue be and why is it giving me this much trouble?

AMD Duron 1.1 Ahhaa could the stepping be the problem?