Back where I started here...problem as before refuses to boot into Vista. This problem comes on gradually. Won't boot into Vista so you use system restore and then everything is ok for while and then it happens again but more frequently.
So it failed on the 7th April to boot; system restore used and then four successful boots ups and then a failure on 15th. System restore but failure on the next boot-up and the two after that. So its failing every time now. Startup repair always finds nothing wrong - problem signature 6 NoRootCause - and system restore only working on its second attempt this last time whereas before
The odd thing is how the fault occurs more and more frequently. I know if I do a complete reload of Vista, as was done a few months ago, it will probably be ok for while and then it will be back.
In the event viewer this appears on every date of failure to boot..(along a lot of other stuff but this is marked as error..
The entry <C

PROGRAMDATA\MICROSOFT\WINDOWS\START MENU\PROGRAMS\MCAFEE\MCAFEE INTERNET SECURITY.LNK> in the hash map cannot be updated.
Context: Application, SystemIndex Catalog
Details:
A device attached to the system is not functioning. (0x8007001f)
Could this be the cause? Its the increasing occurence of the fault that also bafflles me.
Any thoughts...change to Window 7... or buy a new computer..