mainepcman

Here is a problem and a half. When booting Windows XP home edition, it goes to welcome screen and when user is selected it flashes the destop for a split second returns to Welcome screen and logs off. I am NOT able to go into safe mode. It will not leave Welcome screen if Administrator is chosen and will not go if user is chosen. I have perfomed a chkdsk from dos prompt with no problems found. What could be the problem. HELP!