Hi YG,
It seems that although I can now access the system, some programs are still playing up.
The Microsoft tech guy rang me this morning (as he said he would) to check and see if I had managed to get into my system and find the rogue program.
He was happy I had done that much but said I could phone him this afternoon about the other issues (McAfee shutting down it's automatic scanning option, not being able to log-off or switch user etc).
I wish in hindsight I had taken a virtual image of the system originally. so that I could just go back to that and start again. But if he can't fix these other issues I think I will remove all the necessary data and then do a re-install of Vista to clear the niggles.
Yes, I went into Services and saw that many of the programs had been stopped (no idea why), and I have started some of them but half of them you never know what they do, talk about confusing! I'm fairly well versed in computers but sometimes, the jargon just overwhelms you....

This PC is an Acer Aspire x3200, 64bit O/S AMD Phenom 9650 Quad core processor, 4Gb RAM, 2.30GHz 640GB hard drive. So, it is quite a good machine and has been running very well up until 11th July 2010.
I'm sorry to hear that you're having to pay so much to get your's fixed. Is there no way to get compensation back from Microsoft, given that it was there update that has caused this? Can you get together with some of these other people and form a committee to petition Microsoft? I know that this is a nuisance, probably just when you don't have the time but releasing this update, when surely it couldn't have been tested properly, was totally irresponsible.

Have you been able to go back with System Restore or is that also not functioning? You can do that by either hitting the F8 key and holding down while the system starts or else F12 and trying the Vista options.
I really wish you luck with the repair and please let me know if I can offer any help (small such as it is) with your system.

Kindest regards,
peaches48