I have a portable computer ACER ASPIRE 5520G. When i power on the computer by pressing the power button the power button light on and off but the compter does not power on.

SOURCE: acer aspire 3634 LMi

Have had a similar problem with my 3634.
I was advised to disconnect from the mains and remove the battery. I then had to depress the "on" switch for about 10 seconds. I then reconnected the mains lead and away it went.
Apparently if your battery is a bit "iffy" it can cause the whole thing to shut down even when on the mains.
Hope it works for you - let me know.
Cheers!

SOURCE: can see nothing on screen

press function and f5 at the same time

SOURCE: on acer aspire 5520g the dvd rw spins the dvd but

Try downloading a driver from the net, Or install DVD software such as Roxio or Sonic Cine Player. Does it show in hardware as a CD Rom or DVD/RW ? If it shows as a CD the driver is the problem.

SOURCE: acer aspire 5315 doesnt boot blank screen

When you power up the laptop press F1 or F2 or "del" key to enter in bios setup.
Then check your harddisk is detect or not?
Then also make sure SATA option is disabled in bios.
Then go to boot option and set first boot device as your harddrive.Then save settings and exit.
But if you even not able to enter in bios then you have reset bios settings and Refix RAM memory .
For that open back cover fo laptop and find cmos cell on motherbord pull it for 10 minutes so all settings of bios goes to factory defaults.
Let me know if you need more assistanse.
Thanks.

SOURCE: Acer Aspire 5520g continuous restart on off problem

try cleaning the air vents with a hoover. worked for me mine kept overheating and shutting down it was down to dust