Sorry to hear you are having problems. The very fact you tried an external monitor shows you have some good IT skills. As long as you know this monitor works it is a good test. As you have no image try toggling the video output signal by using Fn (Function) and the CRD/LCD (Cathode Ray Tube/Liquid Crystal Display) keys or Alt (Alternate) and the CRD/LCD keys.
If this does not workthen it is either
1. Laptop on board graphics failure
2. Laptop LCD panel failure
3. Laptop inverter failure
4. Laptop backlight failure
Turn on your laptop and look closely at the screen, can you see what you would normally see but very very dark? If so it is the backlight. If you cannot see anything, which is likely, then it is the inverter, actual panle failure or grahipcs chips on the motherboard.
Above is a link and flow chart that will help you.
It is most cost effective to send or take the laptop in for repair. You can replace inverters yourself but there is guarantee it is that. If the graphics on the motherboard has failed then all you can do is have the motherboard replaced. If the laptop is slow and old it may be time to consider a new laptop. If the laptop is under warranty, goto the Fujitsu Siemens website and log a under warranty repair.
All the best, Phil