have you tried booting off the window 7 cd and tried seeing if using a rollback point will work or run a windows repair. the drive might be fine but the mbr could have issues. you may also have downloaded a virus. if there data you need on both drives then pick up an 8g usb stick and install windows on it. you be able to boot from you pc usb stick..it wont be fast but you should be able to see both drives. and then be able to copy your files to a cd or another usb stick.