Monitor does not detect any signal

So I have had this newly built pc for about a week or so and while everything works perfectly the monitor doesn't detect any signal at all even though everything inside the computer was working

I had the same problem when I first bought the pc. I plugged everything in and used a DVI cable to test if everything was working right but the monitor had a message saying NO SIGNAL in every source.

I then proceeded trying with an hdmi cable but it was the same as before. I called my friend who helped me build the computer to come over and try to fix it since he is a computer technician and he did some stuff with the keyboard I can't recall and the pc booted on bios and the screen finally got the signal.

Now I have been using the PC for about 2 weeks and it has been working perfectly until now when I came back just to find out the same problem has showed up. Maybe its because I tried moving the desktop and the hdmi cable may have been unplugged but I tried replugging it back in but still no signal.

I am sure it is not the monitor since the monitor works fine with my SNES mini which uses an hdmi cable too.

I neither have any idea what is causing this to happen nor how I can fix this. I could call my friend again but he is too busy and I don't won't to annoy him.

If anyone can help me I would very much appreciate it.

By the way everything in the desktop is working just fine too the specs are:

CPU: Intel i5-9400f

RAM: G.Skill 2X8GB DDR4 3200MHz

GPU: Gigabyte 1660 OC 6GB

Storage: Kingston 240GB UV500 2.5 SATA III

Motherboard: Gigabyte B365M AORUS Elite

PSU: Corsair CX Series CX650