Windows 7 constantly crashing randomly

Hi I have been having a big problem with my computer lately. I have a VAIO CS series running windows 7 home premium 32 bit and in the past month it has started to shut down randomly not even going through the usual motions it just turns off and when I try to to turn it back on it continues to turn off even before the system has booted up. After a couple of tries of restarting it the recovery program comes up and has said a couple of different things like a driver is preventing windows from starting, changes to key settings may be preventing windows from starting, a recent patch or upgrade may be preventing windows from starting. Its mainly these three things that are coming up after the recovery process goes through. Also I have tried to restore the computer to a point before it starting shutting down randomly but it is still doing it. I have read a couple of forums and a possible problem might be from it overheating which could be possible because I think for this series the fan can malfunction and the bottom of my computer gets hot fast and sometimes the fan makes a weird loud noise. I have tried uninstalling programs that I though were the cause but nothing is working. If someone could please help I would really appreciate it. Thanks