virtualbox.org

Hello everyone, I am new to virtualbox. I installed it on my windows desktop computer. When I tried to start a software needs to run on a virtual machine, it showed me an error that VT-x is disabled in the BIOS for all CPU modes so I reboot and entered the BIOS to enable virtualization Technology. I saved it and exited. I think the computer reboot again.

Then! All in a sudden, I found my screen went black. But after the computer reboots, I can hear the music as Windows starts, which means the computer is fine but just not send out the display signal.

I tried a lot of things. I disconnected the power and pulled out the battery on the motherboard. I disconnected the jumpers and reconnected them. I pulled out the RAM and display card and then put them black. The black screen problem is till there. Again, every time Windows starts, I can hear the music but the screen is black. I also tried all the connectors, VDI, VGA and HDMI, but none of them is sending out the display signal.

Really don't know how I can get the display signal back.

You changed the Virtualization Technology switch in the BIOS then rebooted and your display stays off, even though the PC boots up. At this point, Virtualbox is not running, so we would not know what to do. Your problem lies in your PC. You'll need to get some help in appropriate places for troubleshooting display problems. However, I'll pass along a couple things I would check:

I would take my display to another PC and try it there, and borrow another display to try on my PC, to see if it is the display itself. All the power plugs plugged in? You have a video card. Many middle-class and low-class PC motherboards have on-board video too, and some BIOSes require a switch to determine if the onboard video or the add-in card is default. Maybe you toggled that switch by mistake?