Windows 7 won't recognize a second MyPassport drive

WD External Drives WD Portable Drives
2

It sounds like a Windows signature collision problem. This thread explains what to do http://community.wdc.com/t5/My-Passport-for-PC/Copy-files-from-one-drive-to-another/m-p/277504/highlight/false#M7587 see post 11

Joe