Computers & Electronics

Troubleshooting desktop computer - monitor, mouse, keyboard not recognized?

  • Last Updated:
  • Dec 25th, 2019 6:44 am
Apr 19, 2014
14 posts
Toronto, ON

Troubleshooting desktop computer - monitor, mouse, keyboard not recognized?

I am having trouble getting my old desktop computer to work and was wondering if anyone has any suggestions on how to troubleshoot/solve the issue. I'll try to provide as much information as possible but I'm not too tech savvy so please go easy on me lol

- desktop turns on: motherboard LEDs light up, PSU fan turning, CPU fan turning, GPU fan turning
- BUT monitor will not turn on (yellow LED light on, should be green when turned on), "HDMI no signal" shows up and screen turns blank; I know the monitor works because it works perfectly fine when plugged into my laptop
- USB mouse and keyboard are not working (mouse LED briefly blinks when computer is powered on); the keyboard and mouse work when plugged into my laptop
- there's no beeping sound at all from the computer when turned on

This specific pattern seems to be pretty common because googling shows up a lot of results.
Based on the search, I have tried some conservative approaches so far:
- replacing the CMOS battery on the motherboard
- replugging the cables on all components
- removing and placing back the RAMs
- removing the GPU
- unplugging optical drive and secondary HDD from PSU, leaving SSD and motherboard plugged in

Desktop specs:
- OS: Windows 10 (home edition I think?)
- CPU: Core i5-3470 3.2Ghz
- GPU: Gigabyte Radeon RX570 (I JUST purchased it and I can't get my computer to work!)
- RAM: 10gb (4 + 4 + 2 from some random company I think)
- PSU: EVGA 500B
- SSD: Crucial M500

History of the desktop:
- the desktop was purchased pre-built from NMICROVIP back in 2013
- GPU, PSU, and SSD were replaced and worked fine for about 2 years
- near the end of the 2 years of using it, I started having some issues. When the desktop was powered on, the monitor would turn on for a while and then turn off. Turning the computer on and off repeatedly, the monitor would sometimes end up working and the computer would boot fine. At that time, the mouse sometimes would not work either (but the LED would light up)
- generally, I had no issues with the computer once it booted but when the monitor went to sleep, sometimes it would not turn back on; I would have to turn the desktop on and off again
- I got myself a laptop and stopped using the desktop all together; Now that I purchased the RX570, I went back to the desktop but the situation seems to have gotten worse.

Could the issue be the motherboard? The PSU?

I'm hoping I won't have to replace the motherboard because it seems like there aren't many of them available that are compatible with my current CPU, which means I would likely have to replace the CPU as well. But if I can't get it to work, I'll probably end up purchasing the AMD Ryzen 5 2600X so please feel free to also suggest an affordable MOBO that would be compatible. Thanks!
4 replies
Sr. Member
Jan 16, 2005
733 posts
Try a vga connector to monitor? Try another PSU with more watts. Adding the RX570 may be demanding on psu.

Strip it down to memory motherboard vga and boot to bios. Reset bios. If you can’t post take motherboard power out of case and put on a board or desk see if it boots.
Deal Addict
Jul 26, 2004
3774 posts
The I5 3470 should have integrated GPU... so take the RX570 out and see if the machine will post. Perhaps it's a Video card and Motherboard UEFI/Legacy Bios issue. I have a i7 3770 machine that came with a motherboard that needed to tweak the bios setting before it'll post on a Radeon R9 280X even.

Also make sure the card is securely inserted into the PCI-E slot.. and also the PCI-E power cable is plugged in.
Sr. Member
Dec 10, 2003
550 posts
clean your heatsink for heavy dust buildup
Sr. Member
Nov 14, 2008
812 posts
from your previous description it sounds like it already had issues, before the new video card.

look at the motherboard and check for any obvious issues, such as fatter than normal capacitors
disconnect all peripherals, dvd drives, hdd,video cards (use onboard)
if still no boot, remove the ram, does it beep?