Thanks again for all your help
I just remembered, a year or two ago I upgraded to CS5 (via the Internet). I had forgotten that, and was bewildered as to why, before my hard drive crashed last month, my version of Photoshop (thinking it was CS3) worked with my raw files. But now I'm realizing it was CS5 via Internet upgrade.
So, I have found my serial numbers for CS5 and am downloading the upgrade now. That should solve the problem, right?
Sorry to waste your time!!
Thanks again!!