what is sounds like to me is that explorer.exe isnt loading on startup, ive had a similar problem, all u have to do is when u load ur computer hit ctrl+alt+delete(if your using xp pro hit task manager then do the following) go to file-new process and type explorer.exe and that should pop up all you Icons and startbar and if that dont work it could be that u have to many things loading at startup and its causing it to load really slow, if its that go to start-run and type msconfig and go to startup and uncheck everything(if u uncheck ur g-card or sound card it's not stopping it from loading its just stopping the icon from appearing in the startbar)
Hope that helps