I was surfing the net then suddenly my laptop blackout. I was using my battery and ac adaptor charger. everything was plug properly. Why does it happen? I scanned my laptop and it shows no signs of virus or spyware. plz help me. thx in advance.

Could be a bad battery and/or charger/AC Adaptor/DC Connector. Try to isolate the problem by removing the battery and then plugging the laptop charger in and starting the pc up. It should boot on the AC adapter alone. If it won't boot on the AC adaptor or it flickers and flashes while on the AC adaptor, I would first suspect the AC adaptor or the DC connector on the laptop (try wiggling the power plug at the PC to try and check the connector). If it behaves while on the AC adaptor without the battery present, I would suspect the battery. Either way, you may have to replace something.

Is the battery any good? A bad battery will cause erratic operation of adapter/charger.

Take the battery out. Unplug the charger from the computer. Press the On button for 30 seconds. Then plug the charger in. If it works, then put the battery back in and you're in business again.

If it still can't work, perhaps the charger you bought is a dead one, just contact the seller to get a replacement one after all you have used it for about a few minutes. If you don't believe in that seller, just contact them for the refund and go to other vendor for a new adapter. I recommend the following one for you:
http://www.chargerbuy.com/replacement-acer-aspire-5739g-ac-adapter-19v-4-74a.html

http://www.chargerbuy.com/replacement-acer-aspire-5738-ac-adapter-19v-3-42a.html

1) The AC adapter should ALWAYS be plugged into the laptop FIRST, then plugged into AC power. If not, this could create a voltage spike.

2) Let's look at the DC Power Jack, for the Compaq Presario M2000 series of Notebook PC's,

http://www.notebookparts.com/products/description.php?II=9741

The DC Power Jack is mounted to a removable circuit board.
Enlarging the view of the jack, shows us there is an Inductor.

The small 'can' standing up on the power board. This chipset could have gone south. (Bad)

How to know? Replace it, or dig out your dual trace oscilloscope. See if the Inductor works.

Could also just be cracked solder joints, of the DC Power Jack, TO that small circuit board. Solution would be to resolder it/them.

[ I WOULD however, search for a BETTER price, than listed in the link above, IF available ]

DC Power Jack is in good shape, soldered tight to the motherboard, and ruled out as the problem?
(Since you know the AC adapter is good)

Then the problem would be the Inductor on that power board, or power correcting chipset.

What one is it? Dunno.
DO KNOW is has J leads on the bottom.
CAN give examples, and perhaps you can identify using them.

1) https://docs.google.com/viewer?a=v&q=cache:oER5NNz8cwcJ:www.fairchildsemi.com/ds/FD/FDS6675BZ.pdf+Fairchild+FDS6675BZ&hl=en&pid=bl&srcid=ADGEEShOhWPjm_M-ROHme4iEMrztCTOd-28jNiy1hVLQQh_VOyv8zcXEVDB_iTQA6MuZO88UmRkDgjyW9j4CP2aIJ-4DS-h6JNM3lvxldeApQeecmz_DADCw1s7tmNLxfPknqX14SZP6&sig=AHIEtbS_rYUAeo_8rB9YHkW05ZjLqeH4Jg

2) http://www.utsource.net/ic-datasheet/KB926QFB1-1829416.html

Service Manual, (Free), for Compaq Presario M2000 series of Notebook PC's,
(Remember, follow Anti-Static Precautions. USE an ESD wrist strap, and connect it's alligator clip to a good ground source),

http://www.tim.id.au/blog/tims-laptop-service-manuals/#toc-compaqhp

Drop down to the line that begins with - Compaq Presario 1100.
(1100 in blue)
Scroll over, click on M2000. (In blue)

(Ignore if you are aware of the following;
PDF file. The computer you are using now has Adobe Reader on it, which uses PDF files.
After you click on the file name { M2000 }, it may take up to 30 seconds, before the first page comes up )

Compaq Presario M2000 series of Notebook PC's, disassembly guide,

http://www.insidemylaptop.com/take-apart-compaq-presario-m2000-notebook/

Regards,
joecoolvette

With my laptop, I held the power button (still with everything removed) for 30 sec to decharge the capacitors. Finally, put the battery back in and plugged in the adaptor and everything worked

Remove the battery and plug the ac adaptor in check wethere the light on the port where you connect the ac adaptor glows or not, if no then check the wethere the ac adaptor is getting warm or not after you plug it in for few minutes if not then ac adaptor has to be replaced.
If the light on the port is glowing then it is likely that the power supply of the notebook has gone bad as it is not able to switch to ac adaptor or the port where you connect the ac adaptor to the notebook has a short circut when the acadaptor pin is connected , better try with a different ac adaptor to be sure wethere the issue is with ac adaptor or the notebook.
My best wishes

try to remove the battery first and plug in the ac power adaptor and see if it works. if yes, then your battery is faulty.

if it doesn't work i suspected that there's a problem with the power socket from your machine. you can check it with the nearest service center near you.

change the charger that is not the same watage. if the writen is the same has defect the charger try another charger to avoid broken you pc

Make sure the light on your ac adaptor is lit when you plug it into the wall outlet so this way you know that the ac adaptor is working properly. If you do get an led to show up then try again, if you still don't get power to the laptop then take out the hard drive and dvd drive from the laptop and try again. If you still don't get power then for sure the motherboard is bad cause that means the voltage is going thru it properly.

as u said that when u plugged in the ac adaptor into the laptop it recognises that the ac adaptor is connected but it does not charge the laptop in this case what u can do is that if have the same charger extra then u can try with the another charger and if the other charger also does the same thing then in this case u need to replace the mmotherboard and if the other charger is working fine in this laptop then definately chage ur aac adaptor.....good luck...

thanks