HP Laptop adding random strings of "4"

[kimprather912]

I'm working on a laptop that the user thought had been hacked because every time he uses it, it will start putting long strings of 4s in search boxes, notepad files, login fields, etc.

I booted it up and the problem occurred offline, so I'm pretty sure he's mistaken about the hacker. I have since scanned with Sophos antivirus, malwarebytes, super antispyware, and the Sophos virus removal tool. They all found what you would expect from random browsing and removed it. I also ran Hijack This and did not see anything out of the ordinary.

It will work fine for a while, then I will click the start button and it will jump to a search box and the 4s will start scrolling, or I'll open a web browser and the 4s will start scrolling across the address bar. Once that happens the touchpad will stop working but I can use an attached usb mouse.

It doesn't look like the keyboard is malfunctioning in any way and all hardware diagnostics I have run are all okay.

This is an HP Pavilion laptop running Windows 10 Home.

Any ideas about what else to try, or should I just tell him to order a replacement keyboard?

Thanks in advance.

 

[velocityg4]

If you are willing to put in the effort. Disconnect the built in keyboard. Then plug in a USB keyboard and see if the problem still exists. But is sound like a keyboard issue to me.

You can also try removing the 4 key. Turn off the computer. Then dampen a Q-Tip with rubbing alcohol (squeeze out excess alcohol). And try to clean the keyswitch.