Your CD/DVD/Blue Ray-Rom may not be on the boot list, or it is but a lower priority then your hard disk. Try changing the boot order in the BIOS, or try hitting your related function key during boot, maybe F12.
Is windows currently working? If so, you should be able to start a new installation of windows by opening the cd in windows and selecting install windows. It'll create a boot record on your hd then restart and boot into the installation program.
If windows isn't working, do you have a floppy drive? You can boot a windows xp installation from a series of floppy discs. Check here: (https://support.microsoft.com/en-us/help/310994 to download the program that'll write you your boot discs. You'll need 6 floppy discs.
Hmm, I've never tried to use the floppies to launch a branded installation, it does say that it's only for normal installations but I don't see what difference it would make, if I were you I'd give it a go and see.
I'm not sure what type of installation disk your Toshiba recovery disk will be, a normal installation disk can be started from within Windows, where it'll write a boot record on your HD then restart, or you should be able to boot directly from the disk. Have you tried both of these?
If you start the installation from Windows and it doesn't boot into Windows setup, check your boot file (C:\boot.ini) to see if the installation made an entry in there.
If you try and start the installation by booting the CD and it doesn't work, does the BIOS flash any messages up?