Avast 4. I have uninstalled using the AvClear4 . I cannot reinstall because at least one registry entry is locked and cannot be accessed. HKEY_LOCAL_MACHINE\SOFTWARE\ALWILL Software cannot be edited or deleted. I am using WinXP and I have tried to give specific permissions to this key to my administrator user account but I still cannot access it. When I try to re-install the program, it will not install citing no permissions and I assume it’s because the installer cannot access this area of the registry either. I really like Avast and I’d like to get this back up and running. The PC was infected with several viruses that appear to have disabled Avast. Bagle and Mitglieder were 2 of the viruses. Can anyone help? I’d really like to fix this.
Run online scanners and see if they can clean your system.
The computer is completely disinfected. I’ve run Norton’s security response and Housecall.trendmicro.com and both show the system as being clean. I have also run Ad-Aware, Spybot, and Hijack This and have removed over 900 instances of adware/spyware. I have also tried to run a registry cleaner to get rid of HKLM/SOFTWARE/ALWIL Software but to no avail.
So what happens when you try to delete the key in Regedit, exactly?
As soon as I click on the key it says: “Error Opening Key Cannot Open ALWIL Software. Error while opening key.” I have tried doing a last known good configuration to restore a previous registry but that doesn’t work either.
What access rights does it mention for that key?
When I try to access the permissions for that key it says: “Security You do not have permission to view the current permission settings for ALWIL Software, but you can make permission changes.” When I attempt to make changes, it simply says “Access denied”
Make sure you are logged in as administrator url=http://windowsxp.mvps.org/admins.htm[/url] and try again.
btw: are you on XP home or pro?
Try taking ownership of the key.
Of course, I assume you’re logged on as an administrator 
Cheers
Vlk
I have been doing it with the administrator account and I’m in safe mode. 
It says that Administrator has ownership
Under effective permissions it says Windows cannot calculate effective permissions for administrator
Sorry. Windows XP Home.
The solution was to run a chkdsk on the volume. I was then able to change the permissions for the registry key and delete it. After that it installed without a hitch.
ok, glad to hear it is solved.