Remove the battery and charger/ac adapter/power cord from your acer aspire 5517, press and hold the power button for 20 seconds to discharge any residual current inside the acer aspire 5517. This clears your RAM and is like a hardware reset. Replace the battery and charger/ac adapter/power cord and turn your acer aspire 5517 on.
Boot in "safe mode". As it starts up press F8, the computer ask you if you'd like to start in safe mode. Highlight "safe mode" and press enter. See if your acer aspire 5517 is booting up ok .
If your acer aspire 5517 boots ok, do the following,
Try System Restore first,
Start Menu->All Programs->Accessories->System Tools->System Restore. Choose the most recent date before you the encountered problem. If it doesn't work, try the next date.
If System Restore does not fix it, as a last resort, you might need to fdisk, reformat your acer aspire 5517 hard disk clean and reinstall OS, that usually fixes all bugs. Before going that route, try following,
Uninstall unnecessary programs and applications.
Scan with a antivirus program
Scan with a spyware/malware program
DEFRAG C:
CHKDSK C:
Clean up and repair registry problems with registry repair software of your choice
If the problem persists, did you check if it could be your acer aspire 5517 power cord or power source problem? Defective or insufficient power supply might cause error messages that are misleading. Take the battery out and power on your acer aspire 5517 with the charger only. Make sure your acer aspire 5517 power jack and charger plug tip are securely connected. Did you notice the power jack loose? You can find acer aspire 5517 power jack on ebay. Fixing and soldering the power jack requires professional skill though. The charger green/blue LED should be on. If not, replace the defective charger.Both acer aspire 5517 battery and charger, especially its power cord/cable, need to be replaced every few years, consider buying a lifetime warranty charger online from company like topmic