Help! I'm being exorcized!
You won't be exorcized if you're not in your grave.
Just go west, be careful you don't return to your grave though!
How do I get into the farmhouse?
Those connectors are very badly insulated.
Put the sprayer on the connectors.
The police are approaching, how do I distract Big John?
Make him think the place is haunted. (It IS now you're here!)
Smash bulb, Cool John, Charge John, pull curtains & push stair.
How do I rescue Sarah?
Use the broken glass to cut the ropes.
You'll have to manifest yourself to show her you're there.
How do I stop Weasel from alerting the gang?
Knock him out and tie him up.
Push the hammer as he enters. Get Sarah to tie him up.
How can I get the briefcase?
You'll need Sarah's help so the briefcase must be unguarded.
After scaring John five times, manifest yourself to him. 
When the gang make a run for it, how do I stop the van?
You can't stop it, so don't let it ever start!
Bend the key in John's pocket.
What should I do to the taxi?
Make it as uncontrollable as possible.
Tell Sarah to let down the tyres.
The buyers still escape in the taxi, what should I do?
Give the buyers a scare.
Get into the taxi; if you had the tyres let down, it will crash.