Hello again, you're welcome
Yes, just rename your old one and copy across. This is so we can keep yours as a backup but it will use mine.
I use ccleaner to clean the registry. Its free and isnt spyware. CCleaner - Optimization and Cleaning - Free Download
It will ask you if you want to do a backup of the regisrty components before it fixes them. I suggest you do this, just incase.
I'm not sure of the cause. It could be a recent update or it could have got currupted if not shut down correctly etc.
Check to see if your Graphics card is compatible with Windows 7 Directx11: Windows 7 Compatibility for : Hardware: Download Device Drivers
I wouldnt downgrade to Directx9 on a Windows 7 Machine. Directx10 and up is the way to go.