On the odd occason when I switch on my PC for the first time I get a black screen with the message 'Windows Protection Error - you need to restart your computer. When I reboot it offers me Safe Mode but if I click on the 'Normal Start' choice it sometimes loads okay, but sometimes I have to boot into safe mode then re-boot into normal mode. I haven't loaded or changed anything recently except for AVG updates.

Anyone got any idea what causes this?

W98 266MHz Pentium2
IE6 SP1
ZoneAlarm
AVG
256MB RAM

Take a look at this article which will lead you through steps to troubleshoot your problem. It will also give you links to other troubleshooting procedures.

How to troubleshoot Windows Protection Error messages:
http://support.microsoft.com/default...b;en-us;149962

Thanks Rueful Rogue.

Now why didn't I think of checking a Microsoft web site for a Microsoft problem! I actually looked at that item two or three years ago for someone else! Must be senile dementia setting in.