New Dell Vostro 400 Desktop

Question

New Dell Vostro 400 Desktop with Intel Quad processor, 2 GB ram, Win XP hangs when coming out of Hibernate or Standby; also hangs when trying to boot on oaccasion. The problems are intermittent. Can only resolve by removing power and then takes numerous efforts to resolve. Have changed video cards and drivers and removed video card without resolution. Have reinstalled XP and moved to XP Pro. All drivers are current.