Setup fails

[Bobf]

I wonder if anyone can shed any light on my problem. (This problem occurs with Tomb Raider Legend, & Anniversary) - the setup programme will simply not run I select English (I've tried all the other language options too) press 'Next' and a message is displayed telling me that if I cancel setup now the programme will not be installed. Pressing back simply keeps repeating this fruitless loop, if I press cancel it completely shuts down the installer.

This happens during auto-run, if I manually run it or if I run the Setup.exe file directly. I should point out that the discs are fine and work on a friends PC and I have previously had Legend installed on this PC and running.