My emachines laptop takes quite a long time to start up. when I press the power button on, the power button turns on but the screen remains black until after 1 hour or more. what could be the problem?

You didn't post the Make, Model of Laptop or the OS you are using. I'll use a Win 7 solution. Boot the Laptop, open the Control Panel, select Power Options, set to High Performance, select Change Plan Settings, set SLEEP to Never, select Change Advanced Power settings, go through the settings , set SLEEP and Hibernate to Never, Power buttons and Lid to shut down. Always shut down and unplug your laptop when not in use to prevent damage from power surges and possible Fire hazard IF the battery malfunctions. A reboot every day will reset the computer.

It looks like your laptop is in standby.
Try pressing power button.or
CTRL-ALT-DELETE- at the same time.
This should reboot your computer.
Failing this:
Remove power.
Remove battery.
Reconnect power.
Turn on.

Have you try to press the F11 button ?
Turn off the computer,press the "Power" button. Wait for the eMachine's computer to reach the screen that reads "Press F11 to start recovery." Once this screen appears, press the F11 key on the keyboard multiple times to make sure that it registers. If the recovery screen does not come up, you will need to turn the computer off and back on again and attempt to press the F11 button again when the prompt appears.
After doing that is only necessary to follow the steps.

Remove the battery and the power cord from the laptop and the press the power button down and hold it down for 30 seconds. Re-install the battery and the power cord and try to turn on your laptop as usual.

try to take out the battery and disconnect the AC adapter. Press and hold down the power button for approx 10 to 15 seconds to discharge any power left to it. Wait for about a minute, reconnect the battery and AC adapter and try to turn it on. If it powers and but does not boot to the OS, try to tap F12 key a few times when it restarts and from the One Time Boot Menu, select Last Known-Good Configuration and press Enter. HOpe this helps.

take battery out, unplug power, press the power button for 30 secs, plug power back in turn on, that should work

I have been having the same problem. At first I thought that the motherboard was fried and the laptop was a paper weight, but I kept it plugged in and kept pressing the power button several times over the days. It would always seem to start (screen remained off/black) and then it would just go off again in seconds. But persevarence has paid off, finally almost after a week it started up like normal and started working again as normal. I then had the same episode repeat a few weeks later, the computer was useless for a few days and again started up as I kept pressing the power button several times a day.

I believe the problem is with the standby mode. Each time the problem happened, it seems like the computer was going into standby mode and the power button was pressed again before it could competely go into standby or the button was pressed again while it was coming out of standby.

To sum it up, nothing is wrong with the cimputer components, there is some problem with the standby routine. Keep pressing the power button and hopefully you can get lucky in getting the computer to start again. Long term, I am thinking about checking whether there was a new flash update that came out that could fix this problem. I purchased the laptop compaq F72US in 2008 and never updated anything. Also worth noting that I called HP and they didn't stand behind their product.

chang youre flix and screen

you try pressing the power button once?  or maybe even pressing any keys.
also try adjusting your power management
vista) start. control panel. power option.  Edit plan settings.
xp) right click anywhere.  properties.  screen saver tab.  power management.

there is a hole on the back usually goldish inside take a pen push it in there hold for a couple seconds and press the power button