When you installed XP on the smaller drive, it overwrote the boot manager for Windows 7. The issue is that XP's boot loader does not recognise the newer OS. Windows 7 know how to start XP, though.
Boot to your Win 7 install DVD.
On the second screen, choose "Repair" in the lower left.
Yeah yeah yeah - finish already....
Done - You should be able to Dual Boot now.
yep, that solved everything thankyou