This may help.
Pavillion hp model t3245 windows xp
This morning on switching on there was a continous bleep sound from the base unit. All things connected to the unit like monitor etc were not comiing on and nothing was working except the blue light on the base unit. Tried unplugging everything and various ideas but nothing worked. Switched off the power and took the side off and switched on to see if anything 'lit up inside' or even outside like me! The bleep was gone and everything is ok.
As you can see I know very little...was it some kind of protection fault? Any explanation would be appreciated.