From
32-bit and 64-bit Windows: frequently asked questions
Can I run 32-bit programs on a 64-bit computer?
Most programs designed for the 32-bit version of Windows will work on the 64-bit version of Windows. Notable exceptions are many antivirus programs.
More links from there. If you reinstall W7 in 32 bit (would mean reformatting and starting again) you'll be fine. And if you buy W7 to install virtually on your mac, install the 32 bit version for this eventuality.
FWIW - JeppView is 32 bit.