[Chrissytd]

I have a Compaq Presario SR1720NX and recently, I have had some problems with it. The problem is that if I turn the PC on in the morning around 10am it doesn't stay on and shuts off(no fan/hard drive noise) around 9pm but the light letting you know that the PC is power on is still on. When this happens, I have to turn the PC off by using the power switch in the back of the PC and if want to use it again, I have to wait about 12 hours. Is the problem with the power supply or with something else? And, how do I fix it?

[crjdriver]

The very first thing I would do would be to open the case and give it a good cleaning with a can of air. Next [still OFF] inspect the heatsink fan and make sure it is still firmly attached ie no broken clips, etc. Now pw ON and make sure the fans are in fact spinning. If not then you need to replace the fan[s] before doing any more troubleshooting.

If you have a known good pw supply, you can install that for testing purposes after you make sure the system is clean.