I have this problem regularly, H.
I've got half a dozen PPC users with Tomtom, and it crashes at least one machine at least once a month.
If you know this, I apologise in advance: when you reinstall, you have to go on the net to activate the software. Your PPC gives your a device code. You key your licence number into the website, and it gives you one, or two possible device codes. If this matches the device code your ppc gave you, then you're OK. If not (and I know from bitter experience), you have to send a really sh!tty letter to TomTom's Customer Services Director in The Nertherlands, expaling how disgusted you are with TomTom's attitude, that you must have bought the software second-hand, and so they won't reactivate it, and how the whole process can take FOUR months, and TomTom staff have started ignoring your emails!
You need to provide proof of purchase etc etc etc, and they will then tell you that it's a forgery etc etc etc and it's a real pain in the ****.
You might be better off contacting them, and asking for new disks (using your proof of purchase, of course).
However, if it's the same version as I run here (TomTom Nav 3), then I'll happily lend you the disks, but with no promises......
PM me if you're interested. I will need them back though, because they belong to my company, not me.
PJ
PS: I've tried burning copies, without success. If somebody more techie than me (that's anyone under the age of 35, it seems) can explain how it's done, then I'll do that for you instead.