Black screen on startup after running antivirus

dalmacietis · 02 Feb 2015

Hello all,

Today I ran superantispyware and MBAM, they found a bunch of adware but nothing very serious. Then since they prompted to restart, I shut down the computer and when trying to boot, I simply get a black screen. How do I manage to boot at least in safe mode to see what is wrong?

Things I have tried:
1. First I assumed I needed to wait for the antiviruses to finish, but after some 10 minutes nothing changed.
2. As far as I can tell, the monitor is working. The ON light is on, and when it is powered on but PC is not yet booted it cycles through words "analog","digital","HDMI" in upper left corner as usual. So the screen is working.
3. I unplugged everything else, leaving only monitor and power cords and tried booting then.
4. UNplugged and plugged back the monitor and power cords and al cords on monitor side.

After this I am still getting the same black screen. What else should I try?

gregrocker · 03 Feb 2015

Can you boot into Safe Mode as shown in blue link? If so run System Restore to see if you can boot into the OS. If so run Malwarebytes again, but this time post back what it finds in our System Security forum for expert help.

If not Boot into the Win7 installation media or System Repair Disk to run Startup Repair which should automate System Restore, but if not then run it from the System Recovery Options.

Otherwise everything that possibly can be done to start unbootable Win7 is in Troubleshooting Windows 7 Failure to Start, leading up to if necessary rescuiing your files to run Factory Recovery or do the superior Clean Reinstall Windows 7.

Any disks needed for repair are provided if you need them.

dalmacietis · 03 Feb 2015

I can't access Safe mode through Advanced Boot Options by tapping F8 or F5 key.
I can't access BIOS by tapping either Esc, Del, F1, F2, F3, or F10 (I don't remember which is the correct key). Also note that I'm using an older keyboard with a PS/2 port. Normally my PC recognizes the keyboard in PS/2 port during boot, but not the one in USB port.
So I don't know a way to make it boot from Windows installation CD.

Would disconnecting the HDDs help access BIOS?

Also, should I test the PSU?

gregrocker · 03 Feb 2015

You should always be able to boot a disk, and the failure to do so is almost always a user failure - likewise booting into BIOS setup. To be sure it's not the disk try booting it in another PC.

Try resetting the BIOS to defaults by one of the methods in Clear CMOS - 3 Ways to Clear the CMOS - Reset BIOS

Sometimes unplugging the HD's will allow a disk to boot, in which case often the disk needs wiping to clear bad code. The files and a System Image can sometimes be rescued by slaving the HD to another PC. But this is rare.

dalmacietis · 11 Feb 2015

I brought my PC to the repairs, and it turns out the motherboard was faulty (some chip responsible for exchanging data with the GPU). So I'll mark this as solved. Thanks for the help.