A few things:
Right click on My computer
then disk management
2: [quote]Naturally they're not backed up on CD[/quote] Naturally they should be :-(
3: [quote]Naturally they're not backed up on CD[/quote] This isn't likely to be a "reasonable sum" sad to say.
4: There is a chance that if you have to format the disk, using a program like restoration will find a lot of the images again.