I accidentally deleted DLL files i needed to run java correctly, if windows needs them how can i get them back?

I was told that windows needed certain dll's to run java correctly, and i can't get them back. I have windows 7 and i need a download to a dll pack of some sort that will help me get java running once more. I deleted the problem that caused the dll's to go missing, and i need help recovering them. I cannot factory default, but i would sure love to. I cant because when i hit f11 on the start up screen i get a blank black screen with a white blinking _ and it doesn't load. Please help me!