Sound problem.

I read through another post about sound issue on a different model laptop but didnt help. Heres what im having a problem with.

Laptop model-XPS M140. Never had any problems other then its not too great video card, but i dont care too much. But today weird thing happend.
I had it playing some soft music in the morning as i half slept half just resting and it was playing fine through its internal speakers not my external DC powered ones. So i wake up and head to my room, plug everything in including my two sets of speakers into the mic jack. I go on to play a little of fable and after i was done (sound still working well with the other speakers) i head out to read and take my laptop with me to play music, but no sound is coming out.

Yes im pretty computer literate so its not mutted not off, it IS enabled, ive reinstalled the driver from my computers install cd and have messed around with settings i have.

I have set as default (only one listed) SigmaTel Audio. I really do not understand this since it was working 3 hours before and then it stopped. Note: it plays fine with speakers plugged in, just no sound from the computer itself.

Thanks for any advice/help.

 

Oh sorry, im running windows xp media edition if thats any help. Just ran a dxdiag from reading another post and got this error when testing the sound.

DirectSound test results: Failure at step 19 (User verification of software): HRESULT = 0x00000000 (error code)

Not sure what it means or anything haha, so anyone else?