My pc bleeps when switched on but does not boot up. I have checked the battery.

[Mex53]

My pc when switched on gives a single bleep about every 3 seconds. I have changed the battery for a new one, checked memory cards, hard drive and all  connections. It does not boot up windows and the screen remains blank. I have also checked the cpu. I cannot check any codes because all it does is bleep.  

[WAWood]

@Mex53 

If, as you claim, the laptop is really running Windows XP, then the drive has most likely died by now -- and that would prevent it from booting.

If it is failing, it would need to be replaced and there is no point then in doing anything else until we confirm that.

To check the drive you have to follow these steps:
1) Press Esc key repeatedly, several times a second, while rebooting the laptop. Do NOT hold the key down, just press it over and over.
2) Eventually, you will see an HP Startup Menu
3) Press the Function key for testing the hard drive (usually F2) and let it run.
If the drive checks out OK, then report that and I can provide you options for reinstalling Windows on your PC.