Drivers for peripherals are indeed a possible problem. However, you can search the manfr's website to see if there are appropriate drivers, and also search the Windows 7 hardware compatibility list (may be hard to find now) to see if the driver is included in Windows 7 itself.
In general, any 32-bit application will run fine on 64-bit (but not vice-versa).
Interestingly, MS actually recommend that Office 2010 / 2013 32-bit versions should be installed (unless you absolutely need the 64-bit version, think > 65,000 rows / columns in Excel), due to problems with compatibility of VBA & macros.
SD