My Sony Vaio laptop won't reset

Hello,
I have tried to reset my Sony Vaio Laptop to factory settings but it says that it is "Unable to reset." It says "A required drive partition is missing." I am not really sure what this means, and I really need to reset this laptop. Whenever I turn it on, websites keep popping up insessently, and I've gone through all the programs saved onto my computer and I've deleted all the foreign ones, but I could not delete some of them, and I think they are the ones causing the trouble. I just want my computer to work, I do not care what happens to anything I have on it.