Computer will only restart using last known working config

When I restart my computer it gets stuck on the startup screen. After I turn it off (by holding down power button) and back on, it gives me the option to use last known working configuration, and then it will start… I tried to Google a solution, and am thinking it might be a driver issue, but it’s been doing this since the 5th of February (according to my antivirus update logs- last completed update) and I have no recollection of what I could have possibly installed that my computer isn’t liking. What can I do to fix this?! I can’t update my antivirus and I don’t want my computer to blow up… not to mention I can’t install anything that requires a restart to take effect.