I suggest you do a virus scan on those computer to see if anything is found
Wuauclt.exe is a legitimate file name for the Windows Update client. There are many
free products to scan such as the one from Trend Micro called Sysclean in the link
below. --- Steve

http://www.trendmicro.com/download/dcs.asp
http://www.trendmicro.com/download/pattern.asp --- pattern file.

"David" <David@discussions.microsoft.com> wrote in message
news:27896D09-3977-4793-B5AD-44BA54FF9D8F@microsoft.com...
> Recently some end users are unable to login. After they type the username and
> password, the sand glass appears and nothing happens. Only Task Manager is
> available, nothing else shows up on the screen. I have found that removing a
> file called wuaucls.exe allows them to login normally. this file is loaded
> several times, even as a service, and it is under a group called Windows
> Security Control. I have tried to find info regarding the file but strangely
> I haven't been able to find anything, only a couple of German pages that I
> can't read. I hope somebody can help on this one. thanks.