Monitor will not display

Rebooted my hp pavilion and on restart monitor would not display. System seems to be starting on cpu. Monitor is fine on hookup to second tower (toshiba)
When hooked up to hp it seems to go directly to sleep mode. I can get it to do something by fooling with the settings button on front. It goes through a color cycle full screen rgb. Any ideas?

TIA

Danny

 

Danny,

Does your HP make any beeping noise upon boot up? Did your machine lockup or freeze before you rebooted it? Have you tried disconnecting everything from your HP other than the monitor, keyboard, and power and then turning it on? When you turn on your HP does it sound like it is starting normally or does the CPU fan spin more loudly than usual?

 

Yes the machine was beginning to freeze sometimes, and I didn't hear any beeps on startup. It's not making any unusual sounds on starting at all. Should I try taking the battery out of the motherboard for awhile and then try to reboot?
Thanks for the reply.

Danny