Ok so this is what happened... yesterday I came back home to see my computer turned off, I hadn't turned it off. So I boot it, it starts and then stops. The fans start up and the drive also but then complete shut down. For it to restart I had to cut the power and replug. Then it did the same little boot and stop. It has been doing that since I switched from a 40HD to a 200HD, does that take more power since I've only encountered this problem since my HD switch. Anyways I went and took my other comp, this one, and loaded my 400w PSU in it at first it would work but I changed the cable to the HD and it loaded fully. So I closed it and put the HD in place and went to bed. This morning it won't even START with either PSU not even the fans. My mobo green light for power standby is on but it wont turn on. Is it my Mobo or only my Power switch... and should I get a 400w psu if I run A7N8X-X Athlon xp 2600+ Barthon Sapphire Radeon 9200 or something low... 768 pc3200 memory 200g HD Printer/Scanner/Mouse off USB ports 1 case fan 1 heat sink. So before I go and buy a new A7N8X-X board and 400+ PSU I wanted some advice Thanks.