Thanks to all that replied.
Eventually, we found that our anti-virus was the culprit.
We're all good now.
In Reply to Gerry Champoux:
I am preparing to deploy CE Pro 5 M070.
Installing and configuring the 64-bit version worked fine.
However, after installing the 32-bit version, there's a problem (Windows XP).
When launching, nothing is displayed at all.
The trail file isa created and contains only:
Error loading font file font.ndx
Cannot initialize message system; index file msgtxt.ndx not found.
Exception - code was -1073741787.