the only thing I can think of is to roll back to sp2. I am not sure exactly what’s wrong with your system either (probably sp3 is expecting your hardware to do something it can’t handle, such as load too many drivers or something). It’s possible that you have a faulty (eg burnt) RAM, or simply not enough. In fact, there are a lot of possibilities. But the best thing in order to have a working system is to roll back to sp2 (which is what I use and is pretty stable).