OT: CS3 hangs while closing

I've search for a solution/cause for this problem but no joy so I hope someone here can give me some tips.

Phtoshop CS3 hangs when I close it and I have to force a shut down. Here are some details:

XP Pro
4 gig ram
Plenty of HD space - 2 drives.
Recently (today) downloaded and installed latest version of ACR

I haven't done anything new to the machine other than purchasing Topaz Adjust about a month ago but this problem just started this weekend. I did double check to make sure the ACR version is in the correct folder. (Common Files/Adobe/Plug-Ins/CS3/File Formats)

I've rebooted the machine and searched Google and Adobe's site - all to no avail.

I'll be grateful for your suggestions.

Regards,

Linda J