I HAVE A ACER ASPIRE 5100 & WHEN I TURN IT ON THE SCREEN IS BLACK & WONT DO ANYTHING. THEN ABOUT ONCE EVERY SO OFTEN IT DOES BOOT UP BUT TELLS ME THAT I HAVE TO REINSTALL WINDOWS & WHEN I GOT TO DO THAT IT WONT BOOT UP JUST BLACK SCREEN. ALSO WHEN I PLUG IN MY CHARGER IT WILL CHARGE FOR LIKE 5 MINS THAN IT EITHER THE LIGHT STARTS TO BLINK OR GOES OUT? PLEASE HELP???

if you have power it's not the power supply. It sound like the screen maybe gone on your laptop. Have tried hooking up a monitor to your laptop to see if the screen will come up?

Since you have video with an external monitor your lcd panel is going out.This is not hard to repair only costlyhttp://www.insidemylaptop.com/remove-lcd-screen-replace-inverter-board-acer-aspire-5100-laptop/

https://www.bleepingcomputer.com/download/windows-repair-all-in-one/

could be a bad inverter

This is probably a hardware issue with the monitor. Just to make sure, uninstall, and reinstall the monitor's driver. If that doesn't fix it, it's a hardware issue.

You will have to either take it to a shop, or contact the manufacturer (your computer should be under warranty if you've had it for less than a year).

hope it can help you
http://www.drivers-software-download.org/tag/acer-aspire-5100-drivers
http://drivers-download-driver.com/tag/acer-aspire-5100-drivers
http://laptop-notebooks-drivers.com/tag/acer-aspire-5100-drivers
http://driversdownloadsfree.com/tag/acer-aspire-5100-drivers
http://driversdownloadsfree.com/tag/acer-aspire-5100-drivers

Your harddisk MBR sector might be damaged, google fix mbr and resetup your harddisk mbr. After that it most likely will boot.

might be a bad hard drive.

The bios beep codes indicate the video card is not working, so you won't see anything on the screen.

Your video card is either dead, or is not contacting the board correctly.
If you are keen to open it up I will offer instructions to assist you. But in reality, your safest bet is to take it to a laptop shop and get them to do it. There are a lot of tiny screws in these things.

hmmm...anything at all on screen?