Verify in the bios, the boot-up device selection was "saved" before exiting the bios.
Next, just what version of win7 do you have/working with. The upgrade or full version, or is this some OEM type? Its important to know and proceed with.
You may want to use the windows 7 forum, for more possible answers and/or users that are windows savvy.
Im installing windows 7 for a friend and it isnt reading the install disk althought the DVD drive is working fine..
I put in the disk
Change the BOIS settings to DVD boot
restart the PC and it shows a blinking _ intill it starts loading up XP..
Also i tryed the Disk on my PC and it works fine..
and i tryed booting off USB and no luck ither..
Dell optiplex GX260
1793 Mhz CPU