If you have ever moved a working Windows 7 (Or Server 2008) disk to new hardware (say you have changed the Motherboard) then you have probably come across the issue where on booting you find it getting stuck in a loop rebooting every time it gets to the windows screen.
This is often caused by the disk controller having changed and the drivers not being enabled in the old Windows build for the new hardware. Short of doing a full reinstall this can be a difficult issue to solve.
Fortunately the lifesaver that is cdob over at the CD forum on 911cd.net has come up with an answer. His fix_7hdc script can be run from a Windows PE3 environment (recovery mode on a Windows 7 boot disk for example) and will interrogate both the old disk’s windows install and the new hardware to find if any disk drivers are not activated or installed. Even better it then injects any required drivers into the old disk’s install. In every case I have tried this – and I have tried quite a few – I have immediately been able to boot the old disk in the new hardware.
I would strongly adding this tool to your box of tricks now before you actually need it.