Thank you very much everyone - there's clearly some bitter experience out there!

John in Kansas: You're absolutely right, there is a VirusScan logo in the control panel - I hadn't noticed it. Clicking on it throws up the message: "An error occurred while Windows was working with the control panel file C:Windows\System\AVSMCPA.CPL"

I haven't looked at the demo disk for a removal tool, so I'll try that, and the 'readme' file.

I've been through the Start - Settings - Control Panel - Select "Add/Remove Software" routine, and McAfee does show in the list as you suggest, which would seem to indicate that it's been installed normally. But clicking on 'remove' only starts the McAfee installation wizard. The first few steps are the same whether installing or removing, and either way it gets as far as 'internal error 2735' and grinds to a halt.

I tried 'Find Files', searching the C-drive, and all it could find was two McAfee internet sites. No sign of a Mcafee installation in any of the folders.

Saulgoldie: The problem is getting it to uninstall so I can then re-install it. Whatever I've tried so far, it's preventing me from uninstalling it. As soon as I unravel the mystery I'll take your advice and run Win Doctor!

Bill D: I've also heard good things about AVG, so I'll try that too.

Jim: Have tried Add/Remove (see above), but not safe mode, so I'll try that. The trick is to tap that F8 key "gently", is it?!

Thanks again everyone - including those not mentioned by name, I've read all the posts and it's all grist to the mill. I'm going to sign off now and try some of those suggestions. If I fail to re-appear in four minutes, don't worry, it's not Apollo 13! Actually, I'm going to be up all night listening to an even greater source of mystery and frustration: how to beat the Australians at cricket. Removing McAfee has nothing on that.