The correct way to delete an OS is to delete it's partition, not the windows folder which will give you all kinds of problems even if you
Take Ownership. But to do this in a dual boot you must first move the System Active flags to the other Windows partition.
However in your case the other Win7 on E is on a Logical partition which cannot be marked Active to receive the Win7 System boot files.
To solve this you would boot free
Partition Wizard bootable CD, rightclick on the E to Modify>Convert to Primary, click OK. You will also need to repeat this on D and F since they are not contiguous as a Logical extended partition must remain. Then click Apply.
Once E is Primary, you can rightclick it to Modify>Set to Active, OK, then click on Disk # to highlight it, from Disk tab select Rebuild MBR, OK, Apply. Reboot to see if Win7 starts. If not run
Startup Repair - Run 3 Separate Times until Win7 starts and E holds the System flag. You can then delete the old C partition and create a new partition there.
Also, if you did not boot the Win7 installer when installing to E it will not be C when booted. Plus it is more desireable to have Win7 on C in the first partition slot.
So if you want Win7 to be on C when booted as it normally is when installed correctly from boot, I would consider reinstalling after moving all data off the HD, deleting all partitions during reinstall, then creating new ones to format, install Win7 to first install partition.