Since last 2 weeks Windows Update is not working at all. No "Updates are available" messages. When I run Microsoft Update, it opens IE 8. Doesn't matter if I select Express or Custom, it is stuck for hours at "Checking for the latest updates for your computer". I have tried repeatedly at different times of the day.
Automatic Updates enabled and service is running. Background Intelligent Transfer Service (BITS) is running. I have tried setting all services to default like BlackViper says for XP Professional SP3 and all seem to be fine.
I have run all Microsoft FixIts I could find including http://support.microsoft.com/kb/971058 and also performed all manual repair steps on that page. All successful but no change.
Microsoft Security Essentials is getting updated properly but earlier I was getting updates for it via Windows Update also. Scanned for viruses, trojans and rootkits many times with many different programs. Nothing detected so far and I believe system is clean.
I need Windows XP on this system so what can I try next to fix Windows Update?