CPU Unlocking Phenom x2 550

Hi peeps

Just got a Gigabyte 770T UD3P and Phenom X2 550. Tried the core unlock with BIOS F2C and it works great with XP but I have dual boot with Win 7 RC and that will not boot.
Any ideas, help much appreciated

 

Probably not a good batch then. Or check your clocks. What's more apparent to me is that this chip is probably one of the not so lucky ones, so on some boots won't really work.

 

Were both OSes installed when you unlocked the cores?

 

Both Oses were installed and working.
Update
Done some tweaking this morning and after dropping the mltiplier to 14.5 can now boot into Windows 7 with standard core volts. So now have Phenom II x4 B50 running at 2.9GHz.

I was going by other peoples' experiences and left mltiplier at 15.5 and increased core volts only which didn't seem to work.

 

Try running Prime 95 or something- I hope it works, if so you're pretty lucky.