Right the First thing i think of is; are you Burning Your Disks at Max Speed? If you are try burning At 4x As this sometimes burns wrong.
1) Is the Motherboard up to date? Recent Buy?
3) is Have you removed all Usb and Other Ext. Devices When trying to boot from the Disks?
4) Eject the Windows 7 DVD after it freezes, and reinsert it
5) Is the Hard Drive Set up Properly? So Sata set to Compatible in The Bios? Or IDE to Master on the Physical drive?
6) Finaly the only other thing i can think of is What PSU are you Using? Sometimes it doesnt like the Power Supply if your using the new Intel i7 or New Motherboards