Windows XP takes forever to boot up

2700T Presario laptop is running awful. It hangs on black screen forever; and, all of a sudden the hibernation is no longer available and when it times out i have to log back in, which it shows my username as having 3 users at once, for instance after it has gone to standby after only a few minutes away, etc.; I don’t have a clue, and have tried things for past week, like restore to workable settings, etc.
Help PLAEASE.
thanks pamela