My computer doesn't turn on, there is only black screen when I push the power button. What should I do to fix it?
If your computer doesn't turn on and only displays a black screen when you press the power button, there are a few things you can try to fix the issue:

1. Check the power source: Make sure that the computer is properly plugged into an electrical outlet or power strip, and that the outlet or power strip is functioning properly. Try plugging in another device to the same outlet to see if it works.

2. Check the display: Make sure that the display is properly connected to the computer. If it's a desktop, check that the cable connecting the monitor to the computer is firmly attached. If it's a laptop, try plugging in an external monitor to see if the issue is with the display.

3. Remove peripherals: Disconnect any external devices such as printers, scanners, and USB drives from the computer, and then try turning it on again. Sometimes, a peripheral device can cause an issue with the computer's boot process.

4. Boot into safe mode: If your computer is turning on, but you're only seeing a black screen, try booting into safe mode. To do this, turn on your computer and repeatedly press the F8 key until you see the Advanced Boot Options menu. From there, select Safe Mode and see if your computer boots up.

5. Check the hardware: If none of the above steps work, there may be an issue with the computer's hardware, such as a faulty power supply or a failing hard drive. In this case, you may need to take your computer to a repair shop or contact the manufacturer's support team for assistance.

If none of these steps work, and your computer still won't turn on, it may be time to seek professional help. A computer repair technician can diagnose and fix any issues with your computer's hardware or software.
I think my power supply is making a whining noise when plugged in. What should I do?
If you suspect that your power supply is making a whining noise, there are a few things you can try to diagnose and address the issue:

1. Check the power supply fan: If your power supply has a fan, it's possible that the whining noise is coming from it. Make sure the fan is clean and free of dust and debris. If the noise persists, you may need to replace the fan.

2. Check the power supply cables: Ensure that all the cables connected to your power supply are securely plugged in. Loose connections can cause electrical interference, which can result in a whining noise.

3. Check the load on the power supply: If your power supply is under a heavy load, it may emit a whining noise. Try unplugging some of the devices connected to the power supply to see if this reduces the noise.

4. Replace the power supply: If none of the above steps resolve the issue, it's possible that your power supply is faulty and needs to be replaced. This is especially true if the whining noise is accompanied by other symptoms, such as a burning smell or sudden shutdowns.

In any case, if you are unsure about what to do or you don't feel comfortable working with electronics, it's best to seek the help of a professional or a knowledgeable friend to avoid the risk of electrical shock or other hazards.