Backup attempting to make a system image of my E: drive

Current configuration: Win 7 Pro 64-bit, C: (Windows) drive is 500G, backup drive is 1T, (E:) Games drive is 2T. I have Backup set to include a system image during execution.

A while back I downloaded a game from Steam onto my E: (Games) drive which I've done for years now (never my C: drive).

That game installed a copy of .NET onto the E: drive. Seeing that there already is a copy of .NET where it is supposed to be (C:), I deleted the folder. However, ever since Backup wants to make a system image of both the C: and E: drives. Seeing that the backup drive is only 1T, Backup fails.

I opened disk management and checked to see if the E: drive was flagged as a system disk, which it's not, but it's also not marked as 'active', just 'health/primary partition'.

The only way I can get around the backup issue is by shutting off the PC, removing the E: drive, and rebooting. Then Backup only sees the C: drive. However, this is getting old-hat and sometimes produces weird results such as leaving the E: drive icons with the default picture, not the game title picture, after reinserting the E: drive after a successful backup.

Making a long story short, I've looked in the registry for a windows backup parm that reflects both drives but cannot locate anything. Is there anything else I can look at/change to eliminate the E: drive 'system image' so I don't have to mess with removing/reinserting the E: drive?

Thanks.

I tried all the links: marking the partition inactive and starting backup, trying to create a system image (where the selection boxes for C: and E: are grayed out and not selectable.

So, is there a parm in registry that I can search for that shows both drives or is there another procedure I can follow?

Don't bother fooling with the registry. Uninstall .NET from the E drive if you have that option in remove programs.
Or just uninstall .NET in remove programs. Then reinstall to the C. You might have to reinstall the game, but it should allow you to NOT install .NET, or at least allow you to direct it to the C.
If not, that's a really stupid installer.