How do you get the Iomega eGo Hellium 350GB hard drive to be recognized and initialized by Microsoft Vista Operating system? Have tried the instructions from Iomega and they do not work. The system recognizes the drive, but without any designated drive letter.

How does it show in your computer Disk Management? Is shows RAW file system there? Honestly, without important data stored inside this external drive, merely format it there to activate it there manually. But, if you do have left much data there, do not format it easily and recover the data with RAW file system drive data recovery software to see how much original drive data could be restored back.
No matter what your conditions are, always prepare drive data backups on different devices in case of data loss troubles.

Click start all programs accessories open windows explorer you will see your drive usually C: unless its a usb it might be another D: E: F: in your case it will not have a letter right click select RENAME
hope this helps

One thing that is possible, is that you may have another drive letter assigned to the letter the iomega is trying to use.

Try this....Click on your start orb and type in Disk Management.
open the Disk Management utility in Windows and see if you see the iomega drive listed in the list of disks on the bottom.

If you DO see the iomega drive there, make sure it shows a healthy partition (It should say something like Fat 32 or NTFS as the file system type...if it shows "RAW" or "damaged" or something like that, you may need to erase and format the drive)

Then, try right clicking on the drive and choosing "Change Drive Letter and Paths..."
from there try a new drive letter in case you already have another peripheral using the drive letter the iomega drive is trying to grab. This could cause Windows to recognize the drive but still be unable to see it in your explorer.

Good Luck