I think I have it figured out, NeoStrider. I will go ahead with the multiple periods! Tiffs DO open up in Photoshop. The problem I had with the Tiff that didn't is that it wasn't fully rendered (ie corrupt). So the mental ray/file extension problem is officially a non-issue.

There is NO WAY I'm going to get rid of all the nifty MEL scripts I've collected, but preference deletion is always an option in an emergency!

As for 16 bit emulation? I will have to check that, though I don't think it's on. Windows 64 bit is literally ahead of its time. TOO ahead of its time! Thankfully, Maya and my graphics card run on it. I have to have a second computer to do all of my scanning and printing (and run most if not all of my 16 bit programs). Even Norton and Symantec do not presently support 64 bit Windows! (I did find an EXCELLENT virus protection system from an English company, "Avast!", which DOES support XP-64 and does so with excellence).

Anyway, I think I'm back in business, so I will proceed. Thank you again for all your help!