Unable to Delete Registry Key

There are 3 registry keys that I am not able to delete and getting "error opening key" and I am not able to take ownership because there is no permissions. I have already tried to make a .reg file but it is not working, the keys are mentioned below:

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Shell Extensions\Approved\{46D9700D-6DAC-7507-46E7-457874290BE0}
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Shell Extensions\Approved\{4B3E4A36-23CD-FC8D-0BB7-F8E8437CBAE0}
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Shell Extensions\Approved\{C34915D6-DC50-AEBD-57B2-6CCDBFF763AC}

Can anyone help me to solve this problem.

I think that you need to find the DLL file that is being used and then will have to kill it, but remember that the keys are protected.

I am trying to boot with an external WinPE disk and remote regedit and the keys at that point are not being protected. I found out hat a Virus has written to the keys and the security users have been taken care of. I have had this problem before as well but I was not able to find the tool that I used to remove it then.

The answer is simple, you have to use the RegDelNull which is a command-line utility that searches for and allows you to delete Registry keys that contain embedded-null characters and that are otherwise undeleteable using standard Registry-editing tools. Note: deleting Registry keys may cause the applications they are associated with to fail. Download it from here - http://technet.microsoft.com/en-us/s.../bb897448.aspx