Cubase 5 32-bit and 64-bit

I chose to install the 32 bit version of Cubase 5 in 2009 only because I wanted to use older plugins (32 bit only) with it.
Can I now reinstall Cubase 5 (on the same computer), but choose the 64 bit installation now, and have them running entirely separately and independently (not at the same time, of course)? Or will files get overwritten if I try to do this? I have Windows 7 (64-bit).
Many thanks if anyone can tell me this.