display connection trouble

I accidentally pressed the clear cmos button on the back of my desktop, and now when my computer boots up there's no signal from my monitor despite it working perfectly before, and I've figured out it's not a monitor issue. I've tried clearing the cmos/bios, restarting my computer several times...

Hello, recently my display has suddenly started disconnecting, it started about a week ago. suddenly when I was playing a game, all my displays just disconnected. I had changed my PSU recently to a 800W PSU but it started a few weeks after I changed my double 6 pin piggy back (as in a 6 pin...