What would you do next?

[tres]

Laptop, Vista, never really been put on the internet.

Put on the internet, Windows Update does it's stuff
Restarts
Then Internet Explorer refuses to load.
The iexplore.exe process is running, but no active application.

Installation of firefox throws up exactly the same error - process runs, but nothing appears.

What would you do next?

Edit: Ooops, wrong forum, mod please move

 

[tres]

Try safe mode with networking?

Disable any AV/FW?

Safe mode with networking works fine

Will try disabling AV

No windows restore points