Problems installing Knights of the Old Republic

I bought the game, and then began to install it, but when I got to putting the 4th disk in, but computer fails to read the disk. The other 3 disks are fine, and the 4th one looks fine, no scratchs that I can see. Is there any way of getting the CD drive to read the disk? Or is it legal to download a copy of the 4th disk as I already own it? Any other solutions?

I would take it back, but it was on offer in a bargain bin at a shop for only a few quid, and I'd rather not go all the way back to the shop, especially as I think this was their only copy

Its a compaq presario v6000 series laptop(v6254, I think) . I know the game will run as I've played it on here before with a friends disk a while ago(although he no longer has it).

If you need any other information, then just ask, I'll be grateful for any help.

Thanks in advance.

EDIT

I've restarted my computer, and tried to install again. Now it seems like the drive is trying to read the disk, as its being loud and whirry when I put it in, but it still won't fully read it.

It might be a bad disc or it might be your cd drive. Try installing the game using a different cd drive or on another computer. If it is doing the same thing, it's most likely the disc that is defective.

Agree to what madman says.

If you can get that cd to run on another drive or pc? Download a trial of Magic ISO" and extract the content to a folder. Then copy that to a usb memory stick and place it on your own windows desk. Then direct the game installer to that folder when it asks for the 4:th cd. Alternative burn the folder content to a cd. Label it the same as that 4th disc.

http://www.magiciso.com/