Hi Imran j. Sehgal
Do you know about Autorun ?
Check this out carefully from this website
http://technet.microsoft.com/en-us/sysinternals/bb963902.aspxUncheck the the programs if not needed.
Autoruns'
Hide Signed Microsoft Entries option helps you to zoom in on third-party auto-starting images that have been added to your system and it has support for looking at the auto-starting images configured for other accounts configured on a system.
Above are important uncheck first !
Try not to delete the keys use uncheck if can work.