Very Sick Computer

My 4 year, 8 month old Sony Vaio is on its very last legs. This morning everything was normal. I did my weekly backup to the external hard disk. Shortly after that was completed the computer got the blue screen of death and said something about the usb bus. All day I have fought with it and got various error messages.I had wanted to wait six months after Windows Vista shipped to buy a new pc, but I am not going to be able to do that. Vista ships on Tuesday. My plan is to order a new Vaio AR directly from Sony. I found one model of the AR series online today that is supposed to be loaded with Vista. I am sure on Tuesday Sony will have the complete line on their website.