My Volvo S40 2.4I 2007 is refusing to start nor even crank.All the lights on the dashboard are on, the radio even the car lights are on as well. I tried changing the batteries but then it failed to respond as well.Kindly help me as to what could be the cause of the problem?It all started yesterday after working hours.

SOURCE: I have a 1995 Volvo 960 Sedan won't start

you need to replace the Park Neutral Safety Sensor on the bottom of the Transmission. Should only be a $125.00 part. Your battery and starter are fine. Replace it and iy will be fixed.

SOURCE: 91 volvo 240 won't start after long trips/multiple short trips

If you mean that when you try and start it the engine actually turns over but does not start, then check out the following info (I had a similar problem on my 1989 Volvo 240. It would start fine sometimes, other times it would not start even though it would crank) . It turned out to be the fuel pump relay. 
When you try starting your car and you can not hear the fuel pump turned on (sound coming from the left underside of the car in front of the left rear tire), do the following if you think this is your issue (no cost for trouble shooting and takes 10 minutes to do):
The fuel pump relay is behind the access panel under the glove box. The panel is easy to remove - just unscrew each of the 5 panel knobs/fasteners a quarter turn and the panel comes out/down.  The fuel pump relay is a white plastic cartridge with a wire harness going to it. Just unclip it from the metal clip that retains it and leave it hanging there. When the car doesn't start and just cranks, lean over and tap the relay while you are trying to start the car (tapping it shakes the contacts inside that would normally switch over to complete the circuit when it is energized). If this is your issue and you can repeat the solution by tapping the relay when starting the car, buy a new one (I got mine at www.ipdusa.com for around $14) and kept the old one in the trunk just in case.
Hope this helps.
-B

SOURCE: volvo 850 won't start occasionally

Hey Kolby!

Sounds like you've got an issue with your alarm module, causing the immobilizer to activate (also known as a "start inhibitor"). I'm not sure what type of alarm you've got, but this will probably help you find out if there is something wrong with it:

There is a panel with relays on it behind the dash. At the bottom of the steering column, by the drivers feet, there is a panel. Remove it to get access to the relay panel (just a couple of torx screws, no breakable clips as far as I can remember). Remove the "double size" relay (probably marked 210-211). Put a wire between the terminals 50E and 50F. This will hotwire the immobilizer and make sure that it always activates when turning the key.

Drive around with the wire in place instead of the relay for a while to see if this helps. If it does you'll know that the problem is related to the alarm system. Keep in mind that you will be without alarm and therefore probably also without remote central locking while doing this.
Make sure that the wire is connected firmly enough so it doesn't come loose. You can also put a fuse on it if it makes you sleep better at night ;)

Good luck!

SOURCE: 2003 Volvo S40 starting problems

Volvo 2000 S40. Fantom starting problem. Went to the starter and has no power to soliniod. Will start for weeks then nothing.
Is this a module

SOURCE: Volvo S60 R will not

Pull the immobilizer fuse.wait one minute then reinstall.This only works 75% of the time.