I have the same problem as a few others do, but all of their questions on this are unanswered too! So now I have two problems! My log in is accepted then it logs itself off back to the enter password screen. Does this for any account, safe mode doesn't help,1 person needs an answerI do too

Sounds like the userinit key in the registry may be damaged or altered. Any chance you can restore a back up of the system that was made at a point in time prior to when the problem started? Any idea when the problem started - what changed - any new hardware, software? See this similar thread for ideas.

Are you login in Domain or in workgroup? Might be possible you are runing in low disk space on your System partition and might be possible your profile size is over then space avalibe on local drive. try to login with administrator account and check whether do you able to login. if yes, then make some space on local drive and you will be able to login.