Black screen after PRAM reset

So, the problem started when the hard drive broke. I replaced it with old SSD previously used in my other Windows computer. I did not format it so when booting iMac it automatically started configuring Windows 10. That was strange, I shut it down and booted from BIOS, but the system couldn’t find my flash drive with Mac OS image on it (which obviously was there). I didn’t know what the problem was about, so I let the Windows load up, it worked fine. After that I read on some forum that if having a problem of “iMac doesn’t see flash drive with OS image” I should try resetting PRAM with cmd+Option+P+R shortcut, which resulted with expected reload, however after booting up the screen is totally black. There’s Mac sound of booting, there’s keyboard lighting, however the screen is totally black. I tried cmd+R but it didn’t work. Any ideas how to possibly fix this issue?