I am looking for a freeware backup programme to back up the whole system as well as just data. There seem to be many available – has anyone got any recommended good ones or is it a case of try it and see?

I have tried using MS backup but it seems to run out of steam at about 5-6Gb and says the file is too big. Also, I understand that it is not compatible between 98SE and XP. One of the reasons I want to backup the entire system is that I am going to add XP to the machine and want to be able to revert to 98SE in case (sorry, when) it all goes wrong.