My 6831FX wont charge anymore PLZ HELP!! any help...

I have a 6831FX for about 2 years now. The stock PSU gave out some weeks ago so I bought a universal 120w power unit for the laptop. Today when I noticed at the volt setting on the new PSU said 18volts. When I look at the stock PSU it said 19volts. So I changed the volts settings on the new power unit to 19volts, it goes from 15-20 volts on the settings. I changed the voltage setting while the laptop was charging.

Now the problem is that the laptop wont charge anymore. The light on the new charger just turns off when I try to charge it, so its not charging according to the battery indicator on the OS desktop. I returned the new charger for another one and the same thing happens, I thought the charger was broke. The laptop still turns on and off and everything seems fine with it but its not charging anymore, it runs from the battery just fine.

The specs on the laptop are this:
vista prem 32 bit OS
t8300 cpu
8800m gts gpu
3gb memory 667mhz
640gb drive
stock dvd drive

any help would really be good since I wanted to keep this for another year until Sandy Bridges comes out with a quad core with integrated gpu.

 

could anyone know any good ideas on what to check for?