I have a compaq laptop and recently did a hp update. It switched off (as normal I think to update) but when it came back on automatically it seemed to be stuck on a black screen with a static white dash in top left hand corner. I tried ctrl, alt delete with no effect, would love any advice as really can't afford to pay for being sorted, however will if necessary as kids use a lot. Thanks :-)
Switch off the computer and reboot it into Safe Mode by pressing F8 . Open up the Control Panel and then go to your installed updates and scroll down to the update and uninstall it if you can. Reboot your computer and see if that fixes it. Failing that reboot into Safe Mode and do a System Restore to a date when it was working ok.