This laptop was seriously confused.

The customer lives in a remote area (no broadband, only dialup internet).

He occasionally works in an office, where the laptop gets a chance at operating in a broadband internet environment.

I got called when the PC started behaving strangely (slow startup/shutdown; constant attemts to download and install SP1, error 80073712 during updates, etc).

I try sfc /scannow, but it ends with:

Windows Resource Protection found corrupt files but was unable to fix them

A quick look on the net find a suggestion to try the following from a cmd prompt:

reg delete HKLMCOMPONENTS /v StoreDirty

But it doesn’t work for me.

I try all sorts of ways around this… mostly revolving around trying to remove pending.xml files

I eventually find a solution that works:

Manually download the Vista SP1 standalone install file. Then run the installer, and it seems to take over and correctly install SP1 (even though the automated windows update had previously failed).