Drive not recognized, Win 7 32-Bit, RC1

WD External Drives WD Portable Drives
2

1.  If you have NVidia chipset, try below.  It is specific to RC1 issue with Win7.

http://support.microsoft.com/kb/976972

2.  updated from XP Pro > Vista Home Premium > Win 7 RC1;

Hmm, I my personal opinion it is better to go clean installation as previous OS leaves many residues.