Windows doesn't boot after removing Ubuntu: grub black screen

I had Ubuntu and Windows installed in dual boot. I wanted to remove Ubuntu and, following suggestions online, I eliminated Ubuntu partitions. When I restarted PC I got this on black screen:

"GNU GRUB version 2.02beta2-15 Minimal BASH-like line editing is supported. For the first word, TAB lists possible command completions. Anywhere else TAB lists possible device or file completions. grub>_"

BIOS doesn't start so I can't boot from USB. I don't have factory image because I performed a clean installation when I installed Ubuntu and Windows.

I need help, thanks.

Try this:

1. type exit and press Enter. This will take you to a page where you can boot Microsoft Windows
2. download "visual BCD editor" from www.boyans.net
3. run dual boot repair which is an automatic tool
4. click on Automatic repair and then click OK
5. restart your computer

GRUB is still installed in the MBR, but then does not find its configuration file (because it has been removed, as it was on the Ubuntu partition) nor any modules...

You will have to replace the MBR with the "standard" one. To do that, you can boot the Windows installation DVD, select "repair your computer" (it is on the same windows where you have "install now"), and check if the automatic "startup repair" option makes your system boot. If the automatic repair does not work, you can open the command prompt from the recovery menu, and type this command:

bootrec /FixMBR