Windows stop acer aspire 5520 after I run windows some minute later I feel that windows stop and the monitor is in black, or point and diagonal lines with points

you should re-install your RAM's. it'll be fixed.

thanks

Aspire 5520 has LCD Display. The screen displays becomes dark/ dim if there is no backlight.
There are two parts responsible for lighting the display. First is the CCFL (Cold Cathode Florecent Lamp), which is the back light and the second is the Inverter board, which provides high voltage to the CCFL. These parts are inside the LCD screen. Either of the parts may be faulty or in some rare cases both. Also, the video data cable may be loose or faulty, which can be identified only after opening the top cover.
So, my advice is that you get it properly checked by any professional for replacement of Inverter or CCFL.

Hope it helps! Good Luck! Thanks for using Fixya!
CreativeTECH

Press the Fn key and F7 keys at once.

change comand line to f12 and then its going to ask you to run your program of what windows you have on your system then push enter .

Find a USB memory-stick, and find a computer with Internet access and an available USB port.
Put the memory-stick into the USB slot.
Browse to ACER's web-site, and select your specific model of the Aspire line, and select Windows XP, and select network-controllers, and download the device-drivers, and copy them onto the memory-stick,.
Walk the memory-stick to your Acer, and install the device-driver.

try to re-install your video driver to its latest version.

Try to check on the device manager if the wireless adapter and the ethernet adapters were installed properly. If it appears with a questionmark, uninstall it and try reinstalling it without the ethernet cable connected.

If you are using Vista system, after installing the adapters, go to the network connections and just click on tcp/ip then click on properties. Exit from the window by clicking ok until all windows will be closed for the network connections. Reboot your pc and try if you can obtain a connection.

can you get on in safemode
if you can go to device manager and see if network driver shows then click and update
then do a disk defrag form safemode
please let me know

The black screen with flashing cursor can be caused by the files needed to boot being located in sectors of the hard drive that can no longer be read.

You can try booting to the XP CD, and go to recovery console and RUN CHKDSK /F See if that fixes the file structure and allows the system to boot. If that fails, you can try a repair installation of Windows. If that fails, the most likely resolution is replacing the HDD and reloading Windows and the drivers.

Your system needs audio driver for the sound to work.
follow this link

http://www.acerpanam.com/synapse/forms/acerdrivers.cfm

and download drivers for your system (select your model 5315), make sure you choose the one that matches your OS, that is XP.