Sorry to hear you're having trouble with your notebook.
The book indicator you referenced is the hard drive activity
light. When you see this flicker it indicates the hard drive is being
accessed.
With the notebook booted up, press Fn+F11 a few times to enable
and disable numlock. If the numlock light(lock with the number '1' on
it, next to the hard drive indicator) turns on and off then the problem may be only related to your
monitor and not a failed hard drive, video adapter, or something like that. Believe it
or not this could be a good thing.
With the computer booted up, press Fn+F5 and wait a couple seconds. This will toggle the display modes. Press Fn+F5 a couple more times to cycle through all the modes.
Also try pressing Fn+F6. This keystroke blanks out the display to save battery.
Do you EVER see anything on the screen while the notebook is booting up? You should see the Acer splash screen and maybe some information about entering the BIOS setup.
If you have an external monitor and a VGA cable(or DVI or S-video) you can connect the external monitor to your notebook then turn the notebook on. You may have to do the Fn+F5 keystroke after connecting the monitor to select the correct display mode. This will help us determine if the problem is the notebook monitor or not.
Here is a link to the manual if you need it:
http://global-download.acer.com/GDFiles/Document/User%20Manual/TM_5520_5220_ENG-OLM-0307.zip?acerid=633645712974910948&Step1=NOTEBOOK&Step2=TRAVELMATE&Step3=TRAVELMATE%205520&OS=ALL&LC=en&BC=ACER&SC=PA_7