Here's the walkthrough:
1) Click the note on the floor to get the information for the game.
2) Click down by the side of the yellow filing cabinet to get a little silver key.
3) Click on the filing cabinet proper and collect blue screwdriver in the top drawer.
4) Click on the calendar and flip through it until December and note the guy's birthday.
5) Click the calendar again to reveal a secret panel on the wall.
6) Unscrew the screws with the red screwdriver and then open the wall safe with the silver key. Collect the Zippo lighter.
7) Focus in on the clock and lift it up to reveal a gold key.
8) Open the locked drawer on the filing cabinet and get the ripped up note.
9) Focus in on the desk and using the guys birthday as the code open the padlock and get the snips. (remember to use the American format of the date)
10) Collect the other ripped up note from the bin and then solve both puzzles by moving the pieces around.
11) Focus in on the computer, the passwords are in the two ripped up notes. You need to put them side by side and then just read the three passwords off in a line (it's C3692, 6510 & QT4420)
12) In the computer menu you need to read the details of the safe mode which allows you to cut the wire to the Sensor. I think it's safe mode 2.
13) Start the safe mode and then you can cut the yellow wire without any ill effects.
14) Hold the Zippo lighter to the smoke alarm on the ceiling. After a moment or two the fire alarm will go off.
15) You can now amuse yourself by doing some of the pointless things.
16) After a couple of minutes you'll hear the approaching sirens of the fire service.
17) The firemen will then come and bang the door down (luckily the sensor is disarmed so the bomb will not go off) and rescue you.
Some of the pointless things you can do are:
1) Put the cross on the table by the candles, light the candle and pray.
2) Take the poison table and watch yourself die!
3) Make some ice in the fridge.
4) Fill the cup with water.
5) Scratch your head about that leaking panel on the wall.
6) Turn the tap on the water pipes.