iTunes wont open: Windows 7 64 bit, iTunes wont open: Windows 7 64 bit, iTunes wont open: Windows 7 64 bit

Upgraded iTunes in Dec, hasn't worked since (no problems previously). Won't even start in safe mode.

I've tried all the usual suspects (uninstalled and reinstall both iTunes and Quicktime, deleted SC files, removed all iTune references from Registry etc).

The iTunes appears in Processes for 2 sec only.

Any help appreciated.