For going online to a PP41 you need a serial interface on your PC (USB adapters might or might not work sadly) and you also need to know the proper online settings of your PP41.
There is a nice thread how to go online on a so called “SG3” target:
Determine serial online connection parameters (SG3 legacy systems) - Share Info & Ideas - B&R Community
As mentioned your downloaded S2.7 will be perfectly fine to go online if…
- the serial interface of your PP41 is enabled (within the applicaiton running on the PP41)
- you know (or test out) the serial parameters (for this see the link I posted)
Both PP41 and IF361 are (roughly) 25 years old and back in this days the documentation was a bit vague sometimes
If all other hardware works I still doubt that this is a software issue.
Was this machine running for a long time ? If YES and it now no longer running then this is most likely a hardware issue (as software does not get bad over time)