I have been googling this for hours and it seems that people have had big problems with getting Protel to work on Win7 correctly without having to resort to using a virtual machine with XP.
Also disturbing is many have claimed after installing the program and updating to SE6 it majorly breaks there Windows 7 installation. Then there is the issue with library files not working correctly. Yet some people have figured out ways to get it working fine on Windows 7 but I never see a clear explanation on how they did it.
Just to be clear here I have a Licensed copy here(legit not cracked) that was purchased back in the win 98 era. My Boss does not like the new Altium and is very old schooled and prefers protel, knows how to use it fluently and even occasionally uses Tango believe it it or not.
If anybody out there could please lend me some advice in this matter or offer me some links that might give a guide or instructions on what I may have to modify to get Protel 99SE S6 to work correctly on Windows & I would be indebted.
Like your boss, I'm also old, and I prefer to use some outdated tools with which I feel confortable. However for this case in particular you are dealing with an operational system and a software with a gap of more than 15 years. Perhaps a better alternative could be intalling Protel 99 at XP running under a virtual machine.
I want to share the link of the video file which demonstrates how you can resolve the problem of "File not recognized" in Protel while adding libraries.
I have tested it myself & got 100% result. Give it a try.
Description of Video File on Youtube:
Protel 99 SE "File Not Recognized" Library Error Solution "Windows 7"- Video Tutorial