My Os Drive Is Failing - Trying To Save Data On Pool Drive

I have a self-built WHS - 2 1tb drives, the OS is on the one thats failing.

I've tried moving the pool drive to another machine (running Vista) but the files weren't visible.

The drive was recognized & the system knew that approx. 60 gb was used, but no files or folders were identified.

Is there a way to make the files & folders visible on the Vista box?

If not is there a way to do an install or re-install on the server box without losing the data on the pool drive? I have a spare 500gb drive I could use to put the OS on.

thanks for any help
BT