My laptop all of a sudden kept going into sleep mode, then eventually wouldnt boot up. There is power going to it, power & battery lights on. When I press the power button, it acts like its about to boot up, blue power light turns on, fan turns on for a second, then it shuts off. I took out the battery and tried it with just the power cord. Same thing. Whats going on?

go into your control panel and under power saving turn off the sleep mode settings also check power saving sleep mode settings in bios by pressing f2 at boot also check battery options in security settings hope this helps and yes hp techs are just high paid plumbers reading memos from screens so there not usually much help lol

I find sleep mode nothing but trouble, eventually corrupts window files over extended use, go into power options, go to stand by and select never and click apply, next go to hibernate "top right" and click, make sure the check box is clear, if not! remove check and click apply and restart your laptop.

First advice would have been to remove battery, but since you did that, I'd say that your laptop is stuck in hybrid-sleep, or the old hibernate. Try pressing the power button for 10-15 seconds, the laptop should go off, then try presing the power button again, for normal boot.

No. I don't believe so. I think the purpose of the blinking light is to let you know your PC is not shut down, and is in sleep mode.
If it is a desktop PC without battery backup and the power goes out, you might lose data on anything open and not saved. Or worse it could corrupt the OS (operating system).
If it is a laptop and not plugged in it will eventually run out of juice.
I see many of people using sleep mode exclusively, mostly on laptops.
It is a good practice to completely turn off the PC if it won't be used for an extended time, or at least restarting (warm boot) or shut down (cold boot) once a week so windows can install updates that it has downloaded.
Doing this also refreshes the loaded Operating system.
Your options to stop the blinking light from annoying you would be :
1. completely turn off the PC (recommeded)
2. a small piece of electrical tape
3. A dab of black paint

Try removing the battery, removing the RAM, leaving like that for a few mins, and then put back the RAM, carefully, and the battery, connect to power and hold your finger on the Power Button until it boots, then go into the Power Settings properties, and set your "Sleep" and "Power Saving", & "CPU &Screen" settings from there. Reboot and now you should have your sleep function back.

Dear! take display properties use tab ans select screen saver then click on power and use tab again select hibernate if it is enable check again it and disable now. After that your computer will not go in sleep or hibernate mode.
Thank You

Most likely your laptop is going into sleep mode. Lots of them do not like sleep mode if nothing happens when you push the power button try to hold it down for about 5 sec. your computer should power off and then you can start as normal. If this problem persists change the options in your control panel to turn sleep mode off. That should solve it.

remove the battery and start the machine on AC power only, see if this helps

keep us informed

regards

Do A "Cold" Boot...
Remove The Battery For 30 minutes, And Leave It Unplugged..

With No Battery in and No Charger Cord Plugged In Now, Press and Hold the Power Button Down For 30 Seconds.....

After 30 minutes, Replace Battery and AC Adapter and Attemt to power on "hopefully not in sleep mode"

Removing the cmos battery isn't always enough to reset the bios you may need to find the 'JBAT1' terminal on the mobo and put jumper across pins 2-3 then back to 1-2. But it may be a faulty mobo where the charger connects to the board.