BleepingComputer.com: Can't delete registry keys left by malware

In order to get rid of the malware "powerfulvirusremover2008" junk, I downloaded [Malwarebytes Anti-Malware], which did a tremendous job. Still, four registry keys are left over after a couple of reboots that I can't even delete manually in regedit.
Any suggestions what to do would be truly appreciated (googling and then clicking on some result still "re-directs" me to a site I do not wish to go!

Here is the log after a couple of reboots:

Malwarebytes' Anti-Malware 1.30
Database version: 1414
Windows 5.1.2600 Service Pack 3

11/20/2008 6:24:12 PM
mbam-log-2008-11-20 (18-24-12).txt

Scan type: Quick Scan
Objects scanned: 53017
Time elapsed: 7 minute(s), 43 second(s)

Memory Processes Infected: 0
Memory Modules Infected: 0
Registry Keys Infected: 0
Registry Values Infected: 4
Registry Data Items Infected: 0
Folders Infected: 0
Files Infected: 0

Memory Processes Infected:
(No malicious items detected)

Memory Modules Infected:
(No malicious items detected)

Registry Keys Infected:
(No malicious items detected)

Registry Values Infected:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Settings\bf (Trojan.Agent) -> Delete on reboot.
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Settings\bk (Trojan.Agent) -> Delete on reboot.
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Settings\iu (Trojan.Agent) -> Delete on reboot.
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\Browser Settings\mu (Trojan.Agent) -> Delete on reboot.

Registry Data Items Infected:
(No malicious items detected)

Folders Infected:
(No malicious items detected)

Files Infected:
(No malicious items detected)

Please reboot your computer and update Malwarebytes. This time do a FULL scan and post the new log here