Updates don't install

Mid feb I had a major problem with Vista updates, involving multiple system restores to fix the system.

However, now I am unable to install some updates:

• Cumulative Security Update for Internet Explorer 7 in Windows Vista (KB944533)
• Update for Windows Vista (KB937287)
• Update for Windows Mail Junk E-mail Filter [March 2008] (KB905866)
• Update for Windows Vista (KB943899)

When installing updates, and click help on the error message, it is a WindowsUpdate_800B0100 error.

Manually installing each from the knowledge base fails too.

I tried installing SP1 standalone, as it wasn't appearing in Windows Update, and this fails too: "An internal error occured... Error 0x800B0100... see Error message when you try to install Windows Vista Service Pack 1: "Installation was not successful" or "An internal error occurred while installing the service pack" for details".

I cannot do a system restore, as my earliest point has now been set to my attempt to install SP1.

I upgraded from Xp using an express upgrade disc, so don't know that I can reinstall Vista either.... help?

Fixed it - clean install from express upgrade disc, then upgrade install from inside new vista...

All my problems I had previously no longer exist! Must have been a problem with upgrading XP to Vista...

Doing a clean install is always the best way. When upgrading from one to the other you are left with redundant system files which take up space. Also if you are trying to do diagnostics all the extra folders which are no longer used takes time that would be better spent.