Saw the other thread where the guy lost his storage drive. I too did a Win7 reinstall but my BIOS doesn't even see the boot whenever I plug in the storage drive. Both are WD, boot is 40GB and storage is 500GB.
That's exactly what I did. My other drive bit the dirt. I unplugged everything, installed Win7 on my old XP drive and did all the updates & software installs. Then plugging in the storage drive made my boot drive go bye-bye. I just unplugged the power connector from the storage drive and Win booted right up.
After u plugged in ur storage drive, go into the BIOS and check whether u can detect both HDD and if so, check the boot sequence whether it is correct.
Let's say u have SATA_0 and SATA_1, it is always advisable to connect ur boot drive to SATA_0 and storage to SATA_1. If for some reason that you have to connect the other way around due to certain reason ( like i did in my rig ), make sure your OS HDD is on the list of boot sequence and it is in the correct order.