Why after I log on does the screen go black

Nicky Berridge  … typically, if the log in screen is fully functional and bright as it should be, this will come down to a user setting. (assuming the log in is a windows log in screen) you could try a few things as i see it.

1) try to boot into windows safe mode to disable all programs other than windows itself. (typically f8 as its booting up) If the screen goes back to black, it may be corrupt windows os. you can restore windows to a previous state where you know it was working correctly if you have restore points enabled. (enabled by default)

2) you can try to create another user or log in as a guest to see if this behavior continues. if it doesnt, then it points to a setting on your user account or could point to a virus.

3) FAILSAFE: if all else fails, and you have your data backed up in cloud or another drive ( if not, you can remove hard drive from laptop and connect to another pc via adapter to pull PERSONAL FILES ONLY! do not transfer settings or programs. (in case of virus)

you can then proceed to reinstall windows from either the backup partition or windows management system. (refer to your manufacturers website for restore options) typically this is going to be either esc, f10, or delete.