Vostro 1510 will not boot up. Anybody help ?

Hello,

Here is the situation:

I had to open my laptop in order to fix the wireless card on/off button that was broken. I have opened it before and I am sure that I was following the right procedure, taking care with all the parts. Again, I am sure that I was doing everything properly when putting all the parts together. Now, if I am to start it with battery only, it boots both windows and linux, but close to logging in, the laptop freezes with black screen. If I am to start it with either only AC or AC and battery, it does not boot at all, and the BIOS screen is not displayed eiher. I only see the NUM lock LED flashing and the SCROLL and CAPS locks constantly lid, and thats it. It stays like that and nothing happens. However, with battery I managed to get into windows safe mode and linux command-line and everything seemed fine. I have already reset the memory slot wth the two chips in both places, and the problem stil remains. The weirdest thing is that it boots with battery, but, when I am to use the charger, it does not. And it was all working perfectly yesterday. I do not see what I could have done wrong while taking the parts out and putting them back on.

If anyone has some ideas/suggestions/directions on how to proceed to overcome the problem, please do say them. Any help will be much appreciated.

Regards,

Petar