Windows Vista will not load at Startup

I have an HP Pavilion a1600n It is standard with Windows Vista SP1. I cannot get to the START button on my home page. The computer begins to load normally, then freezes. I cannot click on the stat button to shut it down or to access programs. I am using safe mode w/networking to post this message. Any help is greatly appreciated.

 

I was able to solve the problem by selecting the F8 key at start up, then loading the last known good configuration of Windows Vista. After logging on, and when Windows Vista loaded properly, I then set a Restore point. After logging on and off again a few times to make sure the computer was operating, I went over to the malware threads and did the Read and Run Me First to make sure there were no viruses or spyware causing a problem.

Thanks to everyone who read this thread.