likely there have been some policies changed in the system registry that forbid access to certain parts of the OS. Usually these are set by malicious programs so they can hide on your system without being discovered (and removed) by the user. you will find most of these polices in the registry (Start->Run->regedit) under the HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\ branch. once you get into that section of the registry you should see several values like DisableTaskMgr, DisableCMD, etc you can safely delete most of these values but if you arent sure enough of what it does to delete it, just double click it and change its value to 0
there is a possiblity that you will get the same message when attempting to access Start->Run->regedit if that happens either download and run this file:
Click to view attachmentcontents of attached file:
CODE
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System]
"DisableRegistryTools"=dword:00000000
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System]
"**.del.DisableRegistryTools"=-
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Group Policy Objects\LocalUser\Software\Microsoft\Windows\CurrentVersion\Policies\System]
"DisableRegistryTools"=dword:00000000
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Group Policy Objects\LocalUser\Software\Microsoft\Windows\CurrentVersion\Policies\System]
"**del.DisableRegistryTools"=-
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer]
"NoSaveSettings"=dword:00000000
now as i mentioned earlier, this is likely a result of something malicious running on the system causing this problem so the malicious program might just change the values right back to what they were. even if it doesn't you will want to find something to scan and remove the malware you can try our
Malware Prevention & Security forum for more information on what to use to clean the system.
REF