Have you tried installing the software on a different PC?
Is this a POS (point of sale) system?
Do you run your business through the PC?
What PC brand is it?
Also, go to the start menu>type in “%temp %”> find the 7z folder with today’s date>scroll all the way down to "install" >right click>click on the compatibility tab> Let me know if it's set for XP or some other OS.
Can you upload a snip/picture of the exact error?