Windows 7: Dell Inspiron N7010 monitor won't wake up and needs cold powerdown

This is not a typical BSOD crash. My Dell Inspiron's monitor intermittently doesn't wake up once power management shuts it off. The problem is monitor doesn't fully shut off. One way to know the monitor won't wake up is when the CPU is griding away, fan is on full blast, laptop heated up, monitor still has a faint white brightness but no disk activity. I have tried connecting the laptop HDMI and VGA output different monitors and TVs but the monitor/ TV doesn't recognize any input signal during this phase. Yesterday, CPU suddenly started griding away without a pause while I was working and the base plastic was so hot I couldn't place it on my lap anymore. System Idle was 95-99%; I wanted to check whether laptop will not wakeup after power management kicks and this morning I couldn't wake up the laptop and had to cold boot it

I cannot put my laptop to sleep or hibernate when this occurs, the computer will just keep griding away with fan at full blast but will never hibernate or sleep.

I've run chkdsk, defrag etc but no issues were reported. I have checked for viruses etc, nothing obvious. Any help on what I can do next and how to investigate this further would help.

Thanks in advance

Anyone?

I've had this N7010 laptop for about 1-1/2 yrs without a problem and suddenly it freezes without warning. If unattended, by the time I realize what's happening the fan is blasting away and I have to press and hold the power button to shutdown.

I've reinstalled Windows 7 (Pemium Home), reseated RAM & cleared out what dust I could from the fan vents. The problem remains.

I thought it might be hardware related until I installed Ubuntu and ran for several days without crashing.

I reinstalled Windows 7 again, keeping a careful eye on Win Updates in case there's a problem there... not sure what to do next but I'm pretty convinced it's now a software issue, not hardware.