My windowes XP notbook keeps freezing

I have a windows XP SP3 Acer 8200 travel mate note book and for the last week it has been freezing on me. It does it at different times, the mouse still moves, but does not respond when I click on an icon. I also have had trouble when loading firfoxe, when I open it, it flickers onto the screen for a second and then disappears, I also have skype launching 7 or 8 times which is really annoying. I have run a network diagnostic and my network adapters FAILED and my outlook express mail, Outlook express news and internet explorer web proxy are all NOT CONFIGURED. I constantly need to hold down the off button to shut the note book off as the windows button stops responding when the computer freezes. It usually works fine for the first few minuets and then it freezes. Any suggestions what I can or should do??