windows vista update loop

Hi

I'm trying to fix a windows Vista computer that is stuck in an update loop

It boots up and displays the following:

Configuring updates: Stage 1 of 3 - 0% Complete. Do not turn off your computer.

It climbs to 25%, then after a while it gives up and displays the following:

"Updates were not configured correctly. Reverting changes. Do not turn off your computer."

This second phase lasts forever and then the system boots and the whole process starts again with the initial message.

I have deleted pending .xml from [winsxs], removed blf files from [System32\SMI\Store\Machine] but nothing manages to break this infinite loop, although I did notice that the initial percentage climbs up higher now

The system doesn't boot into safemode, even if selected at startup, the same  configuring updates screen returns.

The majority of reported issues concern configuring updates being stuck in its third stage.

Quite baffling...and time consuming

any ideas ?

thanks
yann