First of all could you please post your system specs..
It sounds to me like you may have a corrupt dvd.. which could have happened when you burnt it.. what app did you use to burn it? Did you burn it on the slowest speed possible? Did you get your ISO from the Microsoft site? Are you using the 32 bit or 64 bit version?
My suggestion would be to re-download the ISO from the Microsoft site:
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Once you have re-downloaded the image then reburn it in XP (burning at the slowest speed possible to avoid the ISO becoming corrupt during the burn) and than try booting off the disc again and doing a clean install on your d:...
That should work as it has worked for many others, myself included..
Depending on your hardware, Windows 7 Beta is pretty good at installing all the drivers for you.. to see if it has be sure to check your Device Manager.. any items with a yellow exclamation mark beside them will need to be dealt with, If you do need to seek out drivers than look for Windows 7 ones first but if you can't find any (there aren't alot out yet specifically for Win 7 so don't get discouraged if you don't find any), than try using the latest Windows Vista drivers as they are all "supposed" to be compatible with Windows 7..
Hope this is helpful to you in at least some small way..

Feel free to report back if you have anymore problems... I and all the other staff here at Windows7forums are always glad to help out the best we can.. Just remember to look around the forum first to see if your issue has already been posted/discussed/solved.
And remember.. ALWAYS MAKE BACKUPS OF YOUR PERSONAL DATA BEFORE INSTALLING AN OS (ESPECIALLY A BETA OS..

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