As a last resort you might need to fdisk, reformat your laptop hard disk clean and reinstall OS. Before going that route, try following simple fixes to see if the problem goes away.
Remove the battery and charger/ac adapter/power cord from your laptop, press and hold the power button for 20 seconds to discharge any residual current inside the laptop. This clears your RAM and is like a hardware reset. Replace the battery and charger/ac adapter/power cord and turn your laptop 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 laptop works normal.
If it runs normal now, do the following maintenance and tune up,
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.
Use external harddrive for all your future downloads.
If the problem persists, did you check if it could be your laptop power cord or power source problem? Insufficient power might cause error messages that are misleading. Take the battery out and power on your laptop with the charger only. Make sure your laptop power jack and charger plug tip are securely connected. Did you notice the power jack loose? You can find laptop 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. laptop battery charger has its own limited lifespan and does not last forever, consider buying a lifetime warranty charger online from company like topmic.com