making changes in Terminal scares me a little
It should scare you a lot. This wretched thread is full of dangerous, irresponsible fake advice.
this is probably a stupid question, but if I delete this plist, the computer will just replace it with one that is not corrupt?
It's not a stupd question. It's exactly the question you should ask. The answer is no. You'll have a corrupt installation that can only be fixed by reinstalling the OS. You should never delete or modify system components for any reason.
If I choose to delete the ACPI_SMC_PlatformPlugin.kext, this will also be replaced with one that is not corrupt?
Same answer.
I suggest that you ignore everything you've read in this thread and instead start your own with a full description of the problem. You'll have as much chance as anyone else of getting a useful response. You have none here.