Parse Error

every time i start up my computer i get a black screen with a small little window saying parse error and an ok button i have to press it like 7 times before a window opens to enter a password all i have to do is click ok and it finally lets me onto my desktop

my computer also wont let me shutdown i click shutdown and it just goes back to the desktop i dont know if this is part of the same thing or not but both of these problem are getting anoying if anyone could help me plz and thank you