I agree with HotSticks. Try hooking it up slave/secondary to another machine get all your stuff backed up. Second burn a all your pictures to a disk. You should never just have it on a hard drive for this exact reason.
From here there are two things you can try. One is the restore back to another date. The other is you might have software installed that you did not intend to install. Malware, spyware can cause this exact same problem. I have fixed many machines that do this and it will drive you nuts. First see if you can get to a desktop using safe mode. Before windows starts to boot up press F8 until you get a menu screen. If it will allow you to boot into safe mode you should get yourself a flash drive(unless you have one).
Install these programs and run them to see if your system is infected.
Get the free version
http://www.malwarebytes.org/
Also get this one
http://www.superantispyware.com/
Both are the best at removing spywayre, trojan horses, and some viruses.
P.S. if you can get into safemode try picking the SafeMode with Networking. This way you can update the two programs to there latest definitions.
... an error message after the boot sequence fails... anything?
