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#11
The Unallocated isn't the grey (unused space) at end of C, but on the far left side of the System Reserved boot partition.
Make sure you have a Win7 DVD or Repair CD standing by in case repairs need to be made to boot sector after resizing. Back up your files and a Win7 backup image externally.
System Repair Disc - Create
Backup Complete Computer - Create an Image Backup
To recover the space into C, use free Partition Wizard bootable CD, rightclick 100mb System Reserved partition, select Resize, grab and drag whole partition intact to the far left, click OK. Make sure it stays exactly the same size.
Next rightclick C, select Resize, drag left grey border to the left to take up space made by moving 100mb partition, OK, Apply all Steps.
If WIn7 fails to start, boot WIn7 DVD Repair Console or Repair CD to run Startup Repair up to 3 separate times with reboots to repair the System MBR: Startup Repair - Run 3 Separate Times