Possible solutions

• Run memory test

To launch the Windows Memory Diagnostic tool, open the Start menu, type "Windows Memory Diagnostic", and press Enter. You can also press Windows Key+R, type "mdsched.exe" into the Run dialog that appears, and press Enter.

• Corrupted Drivers

If the problem doesn't happen while in the BIOS settings screen (usually pressing the F2 key after pressing the power button) I would suspect a corrupted driver. First of all see if any drivers are corrupted by checking in the Device Manger. I would start with the Bluetooth. Just uninstall but don't delete the drivers and let Windows reinstall by clicking on Action > Scan for Hardware changes up in the menu.

• Defective Easily Removeable Hardware Components

If that doesn't work hopefully it is just an easily removeable hardware component with an intermittant failure. Try removing one at a time and testing each time. I would start with the RAM. For the RAM remove modules (usually there are two) one at a time and also try in each individual ones in each slot. Then Bluetooth, Wi-Fi, etc. Even an intermittantly defective hard drive could cause the problem.

The IFIXIT Repairs Guides will help with disassembling. Click on the blue text below.

Acer Aspire 4520-5464 Repair Guides

Let us know how it goes.