[CentOS] hard disk move to another server

Hello everyone.

I am looking for a way to move a CentOS 4 installed production hard disk to 
another system (which has another hardware).
The first has an nvidia sata controller (sata_nv), but the second has a via 
sata (sata_via).
For all the rest of the hardware it can upgrade well I know, but if the sata 
driver is different, then the system doesn't boot because the proper driver 
is not included in the initrd file (grub still boots OK).

Here is the error message:
Uncompressing Linux... Ok, booting the kernel.
Red Hat nash version 4.2.1.8 starting
mount: error 6 mounting ext3
mount: error 2 mounting none
switchroot: mount failed: 22
Kernel panic - not syncing: Attempted to kill init!

Does anyone know how I could upgrade easily this initrd file to contain the 
proper driver, and even from another partition?
Would it be possible to keep an old config-xx file and do an rpm upgrade 
which would automatically recompile a proper initrd-xx file for that new 
system?

Thanks for any help.
Daniel