lsass.exe - system error

I am in a restart loop that shows me the following message: lsass.exe - system error - An invalid parameter was passed to a service or function.

It won't make it to the start menu of windows and I can't find any help from the F2 setup menus. Am I totally ******* or is there a way to get out of this loop without loosing everything?? Please help!!

 

Thanks for the reply. I tried F8 and several of the available options, such as safe mode, safe mode w/command prompt, and load the last windows settings that worked. Now I am getting the lsass.exe - system failure, but it now has something abnout the password not matching. I don't have it up because I'm frustrated with it, but that is the idea of the message. I am wondering about system restore. How do you do a system restore and would that work?