[CentOS] Initial 5.3 install box froze at end of CD 3

Hi,

With the 5.3 CDS I started an install got through to 98% of CD 3 but I 
was called away.

Came back this morning and the box was on, but had frozen..

Every time I reboot, cold boot, I come up with  black screen..

 Vers 0.97 <grub> Minimal BASH-like line editing is supported. TAB  etc..

Is there a way I can get to CD 4 and continue the install, or am I back 
to the top again??

Thanks

rock