Dell Studio 1555 won't boot

Dear all,

Yesterday my two year old Dell Studio 1555 was working perfectly. I hibernated Windows 7 x64 in order to continue my work today. When I tried to turn on my laptop today the screen just showed a white flash and nothing more. The fans are not blowing, the hard drive doesn't spin up and no beeps are played. After the white flash the battery charge led is turned on for about .5 second. I tried to start with only the power cord, only the battery and both the power cord and battery. They all result in the same behaviour. I also tried to start to start the system without any power source to reset the system. After plugging in a power source the problem still exists. 

My laptop is stationed at my desk and doesn't move very much. I haven't moved it between it working perfectly and now with the fault. 

This are the specs of my system:

• Studio 1555 : Intel Core 2 Duo T6400(2.0GHz,800MHz,2MB)
• Display : 15.6in Widescreen High Definition (1366X768) WLED with TrueLife 
• Memory : 4096MB (2x2048) 800MHz DDR2 Dual Channel 
• Hard Drive 320GB SATA (5400rpm) 
• Optical Drive : 8X DVD+/-RW Drive 450-12155 
• Power Supply : Inspiron 90W AC Adapter 
• Battery : Primary 6 cell 56W/HR LI-ION 
• Graphics : 512 MB ATI Mobility RADEON HD 4570 
• Wireless : Intel WiFi Link 5100 (802.11 a/b/g/n 1X2) 1/2 MiniCard European

I hope someone can give me tips on how to solve this problem!

Thanks