Aleksiej Sawiski
Aleksiej Sawiski voted up Yo Kass' answer

What kind of computer is it? Are you using a monitor?

If so, I would try and rule out issues with your monitor, monitor cable, and the port it plugs into your computer... Before investigating more complicated hardware or software issues.

One way to test them would be to borrow ones that definitely work, and see if … Read more

Aleksiej Sawiski
Aleksiej Sawiski voted up Yo Kass' answer

What kind of computer is it? Are you using a monitor?

If so, I would try and rule out issues with your monitor, monitor cable, and the port it plugs into your computer... Before investigating more complicated hardware or software issues.

One way to test them would be to borrow ones that definitely work, and see if … Read more