i know i have a 64 bit, and recently reinstalled uf5.
thats to say, my kid did, and although he said had some trouble, it works.
don´t know,however, if you can run a 32bit programm on a 64 bit computer and if he did that!
i found out that 64bit thing when installing windows7, and uf and xd both have worked on the computer for years.
monica