I got my DVD to force boot this time by pressing F10, then when it asked if I wanted to boot from the DVD to" hit any key", I quickly hit F10 again and it worked!! My BIOS had the DVD as the 1st boot device on both attempts.
Last time I tried it, I hit ENTER rather than F10 a second time, and I did it rather slowly, so maybe it just booted into the 32 bit WIN 7 because I was either too slow or it wanted a second F10 confirm. I can't tell which, but I'm writing this from the 64 bit WIN 7 now .
Thanks for you help!!