My laptop compaq cq40 is not charging, i think there is a problem on the charger

sounds like driver and software issue.. go to device manager make sure the webcam driver is properly installed, if not go to Compaq website or google search for the device driver..

You tried to reinstall the keyboard and touchpad hardware parts? Have you had ANY damage? Spill? OS upgrade? If you replaced the hardware is the ribbon cables connect properly?

Step 1:
If your laptop charger seems broken, it's most likely because the battery will not charge. You plug in the cord, the lights come on, but the charging light doesn't change or blinks repeatedly. When you remove the power cord, the laptop shuts off instantly due to the depleted battery. There's more than one cause for this, and it's not always a broken charger.

Check the connection between the charger and the laptop. It should fit firmly in the DC jack without wiggling. If it is loose, use electrical tape to hold it in place so the charger can receive power. This is a temporary fix, however, because a faulty connection can create sparks and cause a fire or injury. A loose connection will just get worse over time, so have it sent to a DC jack specialist as soon as possible. Turn off the laptop and flip it upside down. Locate the latch that secures the battery and slide open. The battery should pop out; give it a tug if it doesn't. Apply a small amount of rubbing alcohol (Methylated Spirits)to the tip of a cotton swab and use it to clean the battery's connectors. Dirt can build up and interfere with the connection, giving the appearance of a broken charger. Let the alcohol dry completely and re-insert the battery. Slide the latch to secure it and plug in the power cord to test it. See if the laptop powers on with the charger only and battery removed. If it does, the battery is the likely culprit and should be replaced. If the charger is truly broken, the only thing to do is to replace it or the power cord attached to it. Look on the bottom and write down the part number. Call the laptop manufacturer for a replacement charger or search for the part number on eBay. If you purchase from anyone other than the original manufacturer, ask for genuine parts to reduce the possibility of problems. Troubleshoot Mag Safe adaptors
http://support.apple.com/kb/ts1713

Unplug the power supply, take a stiff tooth brush and clean the battery terminals in the laptop plus the battery, re-install the battery and plug the charger in, If that fails you need to find out if the charging circuits are putting out the proper voltage before you replace the battery.

I presume you are running with Windows 7. This is a usual problem with HP CQ40 series running in Win7. Try to do the following;
1. Click Start Button and type at the search field "devmgmt.msc" without the quote.
2. Device Manager will show-up.
3. Click the > at the left side of the "Batteries" to expand.
4. There are 3 options, right-click on "Microsoft ACPI-Compliant Control Method Battery" and select "UNINSTALL". CAUTION!!!: Make sure NOT TO SELECT and REMOVE the Microsoft AC Adapter.
5. After uninstalling "Microsoft ACPI-Compliant Control Method Battery, right-click on "Batteries" and click "SCAN for HARDWARE CHANGES"

You may need to remove and re-connect your AC adapter if that doesn't work at first try.
Five THUMBS UP please... Thank you...

Before you make a decision about the next step, maybe you would like to know why the laptop charger is not working. Here are some commonly found reasons for this problem.

• You have been using the wrong laptop charger for your machine, or someone else has been using your laptop charger for another machine. This may seem like a harmless act, but it affects the battery on your laptop, and charger you are using as well.
• Your laptop battery has become weak and worn out from excessive use. Due to this the battery is not charging at all (or charging very slowly) when you plug in the charger. In this case there is absolutely nothing wrong with the charger itself.
• The wire of the laptop charger has got a distinct curve at one point, and this is restricting it from transmitting power. You need to look out for such bends in the wire, as this will ruin the efficiency of the charger in no time.
• This may sound elemental and stupid to some, but it does happen to many people. Maybe you are simply using the wrong laptop charger by mistake, or maybe you have failed to switch on the power switch. Check both these things to be sure.

Any of these potential causes could be the reason behind your laptop charger not working. As a result of these, either the mains power lead of your charger may be damaged, or the power supply unit may be damaged, or maybe the lead itself is damaged or broken somewhere, or some circuitry inside the laptop is damaged, and not responding to the charger. It's hard to accurately tell which of these problems could be the real cause of your laptop battery not charging, without physically examining the machine.

Solutions and Answers

Now if you are well versed in computer hardware you can attempt to fix this yourself. Most people cannot do this, and it is advisable for them to visit a computer repair shop instead. They will examine the laptop charger not working problem, and suggest some suitable remedies for it. Depending on your budget, you can choose an option that suits you and simultaneously solves your problem. Here are some recommended solutions.

• Buy a brand new charger which will definitely solve your problem of charging the laptop for a long time.

Compaq Presario CQ40 Laptop Charger

• If you're hesitant to pay that amount, you can try and purchase a second hand laptop charger from eBay.
• Get your's repaired and pay the repair shop the fees that they charge.
• If your warranty is still valid, you can simply get the laptop charger replaced.

Reference: http://www.buzzle.com/articles/laptop-charger-not-working.html

Hello,

There are three possible parts of the computer which cause the problem.

1. ac adapter or charger
2. battery
3. motherboard

The charger is working fine which leaves the battery and the motherboard to be the possible reasons for that certain problem. What you need to do is to check which one is really the part that's causing the problem.

Here's what you need to do:

1. Remove the battery from the laptop.
2. Turn the computer by using the charger alone. If it turns on then, the battery needs to be replaced. If it doesn't then it's a motherboard problem which is a very complicated situation. You need to see a computer technician for a motherboard problem.

Has it always done this , or only recently ? HP (Compaq) has a LOT of different models in the CQ40 series. I'd need to know the "model number" or "Service Tag" number in order to help you more.

hi calvinis, you can go to Ebay.com or amazon.com to buy your compaq persario charger, in ebay you have more security in purchasing any product , and you have shipping to any part of world , before searching in ebay , check whether ebay have seperate domain for your country , so that shiping will not take more thn one week to reach you. i have already search one product for you

http://cgi.ebay.com/COMPAQ-Presario-CQ40-CQ45-CQ50-CQ60-AC-ADAPTER-Charger-/250558120799?pt=Laptop_Adapters_Chargers&hash=item3a566d835f

copy and paste about link in browser.

Good luck

find your compaq presario cq40 driver from these site
1) www.drivershq.com/Drivers/Compaq/Compaq-Presario-CQ40.../Models.aspx
2) other wise goto compaq site