See http://www.experts-exchange.com/OS/Microsoft_Operating_Systems/Windows/Windows_Vista/Q_23940872.html (just page down).

If you are SURE the BIOS is set to boot from the recovery DVD (check the BIOS) and it doesn't - or it does and then gives this error - the machine needs repair. It should work.
If you want to backup your photo's first, there are 2 good ways:
1. Boot from a Linux Live CD and burn to DVD using that.
2. Get the disk out, buy an USB2 to IDE/SATA cable and connect it to another PC to read it.
If the disk is broken, none of the two will work, alas.

Kees