Hi, I am trying to help my brother with his old (2005) IBM Thinktank pc with Windows XP Pro. After a recent Windows upadate and restart the PC will not boot. Its stays in a loop. First shows IBM logo, then Windows XP screen then shut off (no signal) and the process starts over again thus the loop! I have starting in tryed SAFE MODE, but I get the same loop. He does not have the CD since he bought it used from a local PC store.