Win7 32bit and 64bit on same machine

Hello,
I have a retail version of windows 7 home premium, which came with both 64 bit and 32 bit DVD's. I have installed 64 bit on my main machine, and all is working hunk-dory.

My question is would it be possible to set up (on a separate hard drive inserted by a caddy system), the 32bit on the same machine?

I would think this is legal as only one copy of win'7 at a time would be working on the same machine.

PS I need this for a couple of programs that will only run under 32 bit, currently being run on my Vista 32 laptop.

TIA ... Barry

Works here. I have the 64 bit version for general use, but the 32 bit version in reserve for a particular peripheral that won't do 64 bit. They are on different drives and they both activated without a problem.

Thanks for that Desmond... Will try it and see how it goes.. Barry