missing key HKLM\Software\Policies\Microsoft\Windows\Windowsupdate

In our environment we are running 3 wsus 3.0 sp1 in a 2k3 ad environment and

configure the clients using group policy and client side targeting. I'm

finding there are 20 or 30 computers out of 1000+ which are no longer

reporting into our wsus servers. I was looking in the registry and noticed

that the HKLM\Software\Policies\Microsoft\Windows\Windowsupdate key is

missing. I was wondering if anyone has ever experienced this and knows what

might cause that and what the fix might be. I can search for these computers

on the wsus console and it finds them as if they had reported in at one time

but not recenlty.

the HKLM\Software\Microsoft\Windows\CurrentVersion\WindowsUpdate\AutoUpdate

key is present and in one particlare computer I checked shows a balloon time

of 6/11/2008 a balloon type of 5 and a nextdetectiontime of 6/19. As this is

6/18 it apears as if the computer knows it needs to check in.

Was hoping someone could provide some assistance.

Thanks