Windows 7 Win 7 not recognizing SATA drive when XP does on same PC

[SSR]

I have XP Pro (32bit) on my C partition (Disk 1), Win 7 32 bit on my F partition (Disk 2) , both are SCSI drives. I also have two WD sata drives 120gb and 640gb.

XP recognizes all drives, win7 does not recognize the 640gb hard drive.

Suggestions please (in addition to uninstall Win 7