Thanks for the replies
Is it XP or Vista?
Vista. It is a desktop.
The solving of the problem by removing the power source and then re-connecting is a strange one.
It took three attempts to get going today. Switched off power at the mains after 1st failed attempt but no joy on second so suspect not the problem. After the 2nd attempt disconnected the modem from the PC and success but again that might not the cause.
"cured" .....by running a registry cleaner program,
I was thinking along those lines..not sure of McAfee has one inbuilt.. Further research on going.