While I know not much about technical malfunctions, see if the followin' links'll shed some light onto yer ordeal, ma'am:
http://h10025.www1.hp.com/ewfrf/wc/document?cc=us&lc=en&docname=c03518165 (http://h10025.www1.hp.com/ewfrf/wc/document?cc=us&lc=en&docname=c03518165)
http://windows.microsoft.com/en-US/windows7/why-is-my-screen-black-when-i-start-windows-7 (http://windows.microsoft.com/en-US/windows7/why-is-my-screen-black-when-i-start-windows-7)
One link is for Windows 7, the other is for Windows 8.