Ok, that's handy enough.
Assuming everything's bought and paid for, you should have, or have access to, installers for all your plugs etc.
For the actual sessions Pro Tools creates a folder by the name of your choice.
Within that folder is the session file (same name) and various folders such as 'Audio Files', 'Fade Files' etc.
Back up the entire folder for each of your sessions.
Worst case scenario, PT may not like that you've moved the folder to a new place and might spend some time relinking the audio.
Don't panic if that happens. As long as it was all backed as one folder, it'll all link up again.
In the ideal world they should all be on a separate drive anyway.
I can't be 100% certain about templates because I don't often use them.
They'll be called "***** template.ptt" so you should be able to spot them handy enough.
If you can't open PT you might want to google "trashing pro tools preferences".
It's always my go-to troubleshooting tool.