I own a HP Pavilion dv2315nr. There are times when the computer starts and QUICKPLAY buttons light up but there is no display. Also, when this happens, pressing caps lock button does not light up its indicator to the left that's why I assume the system freezes even without display. Occasionally, the laptop works only with power cord and not with battery. (Both the cord is plugged and the battery is on) Then, there are times when it works with battery power alone (not plugged, but with battery on) and power cord alone (no battery, but plugged cord). In addition, the system suddenly shuts off at times. Instances like this occur when the laptop is not in use but is turned on and the screen blacks out after the screensaver. The display should be back after pressing keys but it does not. What could be the problem with my laptop? Your opinions would really be great. Thanks.

I believe these are signs of overheating. The dv2315nr uses AMD Turion™ 64 X2 Mobile Technology TL-52 which is prone to high heat. I recommend getting a laptop cooler. I personally use the zalman nc-1000 on my dv6113us which has a similar cpu as yours. If you can't get your hands on a cooler, try using your laptop on a flat surface and make sure nothing is blocking the vents.

If this doesn't work then your motherboard might be failing