Windows Search 4 Update/User Profile problem

A few days ago, Windows Update Automatic updates installed an update on my computer called:

Windows Search 4.0 for Windows Vista (KB940157)

When I restarted my computer after this update I tried to log on and got this message:

The user profile service has failed the logon. User profile cannot be loaded.

I fixed this by booting into the F8 restore options on my Dell Laptop and used system restore to repair the problem
Today Windows Update Installed that same update again and the same problem arose which I again fixed with system restore.
Does anyone have any thoughts on this, like why should this update be causing my User Profile not to load ?

Dell Inspiron Notebook
Windows Vista Home Premium 32bit

Hi, RockLobster, and welcome to the forums.

• Hide the update in Windows Update so it won't try to install it.

• Manually set a restore point - see System Restore Point - create

• Manually download the Windows Search 4.0 update from Microsoft.

• Install it

• See if that causes the same problem - if so, revert to your newest System Restore.

johngalt thanks for the welcome I have browsed these forums many times so today I decided to join and I'm glad I did.
Thanks for responding so quickly to my post I followed your advice and it worked perfectly.
I guess the automatic update must have got corrupted during the download, and now I think back on it, I was having a lot of problems with a wireless network at the time it was downloading.
Thanks again johngalt

Glad it worked. In retrospect, it makes sense - instead of re-downloading the download, Windows Update keeps applying the same corrupted download. If I had instructions on how to clear out the download cache for WU, that would have worked just as well....