OT: Need help with renaming files in XP

[dmm]

Hey all! Some of you are quite good with computers, so here's a stumper for you. I'm trying to rename a bunch of files with names like:
0.1uJ -50 to 50 spot2f.dat
so that they are shorter, like this:
0.1uJ -50to50 spot2f.dat
but the RENAME command in XP has a bug with wildcards if you change the filename length.

For example, the command
ren "0.?uJ -50 to 50 spot??.dat" "0.?uJ -50to50 spot??.dat"
gives
0.1uJ -50to50 spotot.dat
and if I try
ren "0.?uJ -50 to 50 spot*" "0.?uJ -50to50 spot*"
then I get
0.1uJ -50to50 spotot2f.dat

This is driving me nuts! (Note that there are a lot of files, and the names and desired changes are more complicated than I'm showing here, so I do NOT want to do this manually.)

I've checked various forums and can't find this issue.
Any suggestions would be welcome.