Hi all. Can somebody help me. I have a Dell xps. The psu is an nps460 bb d. It is a switching psu....If the power cord is removed from the psu input os I suffer a mains power failure,the system will not power up for at least 5 days. This varies. Once the system does power up, I can power up and down no problem,as long as the mains cable is not disconnected from the psu. If this occurs I'm back to square one and have to wait days. I don't know if its psu or motherboard/sensing . There is no aux power led lit on the motherboard. It may come on eventually....HELP!!!!!