I was looking at a post where the file wuauclt.exe is mentioned as unknown to the poster. A search in 'Startup List" finds it as Malware ... http://www.bleepingcomputer.com/startups/
A google search brings result of it being part of Windows Update
http://www.processlibrary.com/directory/files/wuauclt/

to a trojan in many places. To part of an MS error message
http://support.microsoft.com/kb/312477

What would be needed,the full path, to determine its status. I realize that if you get it from the error message it's dealt with in that manner.

You need to compare the path, the startups name etc. The real file is in the %System% folder. If its anywhere else, it is fake.

Also I don't believe wuauclt.exe is a startup, but gets launched from other programs. (could be wrong on older versions of windows) So if it is starting up from an automatic startup, it's most likely a infection.

thank you Grinler,clearer now