A:
Best Buy has Universal power supplies for MOST computers, try that first. Sometimes after a Windows update, the screen may remain blank until it is completed. This can be minutes, or hours (depending on your internet connection) if your computer has an LED that indicates hard drive activity, it will flash as your hard drive is being accessed. If the screen is blank, but on boot up you saw the computers logo (HP, ASUS, etc.)...AND the Hard Drive LED is flashing, there is a good chance it has not yet finished an operation like upgrading. Leave it plugged in, and check on it periodically to see i it finishes, and boots up.