thanks for your advice various. I turned the machine on the other day and it didn't seem to be able to do much other than idle using 100% cpu to run the task manager. When I tried to switch it off it said installing updates, do not switch off. This was a bit of a worry as I was away from home and didn't have the mains psu with me. I left it running while we had breakfast and it had done 2% of the install when we went out for the day. On return the battery had run out and the machine was dead. When it has had time to charge up a bit I'll give it another try.
Rans6.........