Thanks guys - doesn't happen very often so can't really spot a trend except that sometimes it's happened when I've been trying to open or close new IE pages. Most I use the pc for is surfing the net (places like this) plus watching tv at the same time sometimes. Don't download music/videos or play games on here. What is event viewer and how do I do a scan disk? Ta for the tip about holding down the on/off button - will try that next time.
Remember I'm a novice guys
Oddly enough it happened about an hour after I posted my original message. The wife had been trying to access our email, had some problems and tried to shutdown via the start menu but the shutdown was locked. We switched off/on and got a black and white restore screen with IIRC an F1 option to restore to an earlier date or a carry on to start as normal. I decided on the latter and the machine started up again fine and has been ok ever since. I later discovered my wife had (got to love her
) been resting a tray on the keyboard whilst using the mouse to access our email accounts and I think it had been pressing on some of the keys without her knowledge.