Windows 7 cannot find all Pro/E files in folders

I need hel trying to understand why Windows 7 cannot find all files within a folder structure.

Here what I have:
A top level called "Work"
About 20 folders under the "Work" folder
In one of those 20 folders there are 2 files called: xxx123xxx.asm.1 and xxx123xxx.prt.1
When I search for the string 123 Windows search only finds one of the files but not the other
If I search for *123* then Windows find both

I rebuilded the Windows index but still have the same problem.

Any clues?

Thanks in advance,
Ronnie Shand