SP2 is a nightmare (GRUB ERROR)

[ttrcf]

I have just upgraded (via YaST) a SLED10 SP1 machine to SP2.

Now it won't boot and hangs with the following on the screen:

GRUB loading stage 1.5
GRUB Loading, Please wait.....

and it never gets any further.

This is the 3rd machine that SP2 has completely cocked up. Can anybody offer any advice on how to solve this issue?

Thanks

ROB