Latest update...
I just received customer config.sys and autoexec.bat.
Numerous device drivers loading. Emm386 and himem device lines. CDRom device drivers loading. Anti-virus in autoexec.bat loading.
I don't know whether safe mode by-passes those in one of our tests. I had him move both files to another directory and we are going to test again.

Notes:
1) he can run the software once for as long as he wants with no problem. Exit the program and reenter he will always freeze up his machine.
2) We ran windows resource meter before and after first time in software. No resource losses.
I'll let you know about the test after I hear from him...
Thanks for the continuing support.

Robert