I was getting the "isass.exe -system error endpoint format invalid" error and did a repair install of XP pro 2002. I am now having problems with pop-ups telling me that my registry is corupt and I need to clean immediately. I tried to run my registry cleaner program and it starts but shuts down after about 5 seconds. I went in to the control panel "admisnistrative tools" to disable Messenger and the drop down menus, etc. will not stay open more than about five seconds either. What can I do?