I have a Compaq Presario CQ61 that was upgraded to Windows 10 a few months ago, which is when my problems started. My Num and Caps lock keep blinking w/o end and no POST beeps. I tried removing the RAM but no POST. I tried powering the laptop with only the AC adapter and then with only the battery and still only the flashing Num and Caps lock. What finally worked was holding down the Ctrl-Alt-Delete keys at the same time and then powering on the laptop. It booted right up and began installing Windows Updates. I'm wondering if the Updates had something to do with its behavior. Considering taking this laptop back to Windows 7 with a clean install and getting rid of this crappy Windows 10 once and for all.