I believe you can use the dos MODE command to swop ports.
This can be used in-flight or in autoexec.bat.
You may run up against driver problems, as dos applications each came with their own driver library.
Your specs advise windows 7, is this involved?
If there are problems with the old touch screen, suggest taking it to a electronic (not pc) repair shop. Here in the UK, many have opened with technicians from abroad who work at component level. Generally they inspect and quote for a repair, that the customer accepts or declines.
A a matter of interest, where are you located? I am in Hammersmith, West London.
Good Luck - Keep us posted.