I'm running a 64-bit version of Windows 7 on my laptop. Recently, I found a program called SlimDrivers on Lifehacker which basically automates the process of scanning for and downloading driver updates. Last night as I was running it, an error occured in a driver installation and required a reboot. I went through the reboot and my computer was just hanging at the shutdown screen for about 30 mins, so I decided to hard boot it by shutting it off by the power button. Now, whenever I try to boot my computer, it sits at the "Starting Windows" screen with the Windows logo. I've left it there for up to 6 hours, absolutely nothing happens. I do not have the Windows 7 disc because this was an OEM install. How can I fix this?