HP Pavilion keyboard being odd.

Hello, all! This is my first post here, and I really hope this is the right place to submit this! Onto the small story.. Just a while ago, I was working on writing things down that were important, and my laptop's keyboard has suddenly stopped working correctly. Some keys do not input, and others just throw in random letters. (When I do a space, it does "/. ") I have tried to do as much as I possibly could, which includes restarting my computer and trying to go into safe mode. I restarted and it did not let me type everything correctly in the field needed for my password, it just kept adding on when I pressed one. As it is, I have plugged in a Dell USB keyboard so that I can type. I managed to look at the keyboard properties in the device manager, it says everything is looking okay, i made sure it was not any of the sticky keys or filter keys, stuff like that, and I have yet to figure out the solution. My laptop is a few years old, and I cannot use a USB keyboard forever, so any suggestions would be really appreciated!
My laptop is a Windows 8.1 HP Pavillion, I turned my windows updates off at one point as I signed up for the windows 10 upgrade previously and decided I did not want it when it trashed my other computer I tested it on.
Once more, if anyone has any suggestions or thoughts on what I can do to fix this, I would really appreciate it! I do not want to reset my pc as I do not have my files backed up, I also cannot take apart anything to look for an issue with the hardware and I cannot afford to have this looked at by somebody. Thank you for reading!