The computer in question is a Mac Pro Quad Core 2.66 ghz, early 2008 model. A friend of mine brings over his mac pro today, says he's exhausted all the help he can find on Google, doesn't know what the problem is. I say ok lets take a look. Get everything plugged in and it does something I've never seen before, I'll be as clear as I can: You hit the power button, hear the fans whirr, mac goes 'boom' logon noise. shows the grey/white screen with the apple logo, does the grey spinning circle for about 45 seconds, flashes the usual blue screen....at this point it goes white. The mouse appears in the upper left corner of the screen. There is nothing going on. The mouse is moveable but nothing happens. I've re-booted this thing about 50 times and the only variation is that sometimes the mouse arrow will stay in the corner and if you pull the mouse away from that corner, the arrow will replicate itself and scroll around like a normal mouse while still leaving an unmoving mouse pointer in the same spot in the corner. Sometimes it will turn into the color spin wheel. I thought 'ok this must be the hard drive'. I popped his hard drive out, popped it into mine. Booted just fine. Went off without a hitch. I thought 'ok this must be RAM'. I pulled both of his riser cards, popped out all of his ram, popped in a pair of mine, rebooted. Same problem. Then I thought maybe it was a problem with the SATA connector to the hard drive so I switched it over to the unused 3rd HD slot....same problem. Things of note: -It is keyboard responsive when sitting in that white screen, I can eject CD's all day. -If you boot and hold alt, it will display the snow leopard install cd in the tray as well as the plugged in HD without any problem. If however, you decide to click the snow leopard dvd to boot from it will do the same thing as if you'd booted normally. So no dice there. -It will boot into single user mode with no problem. -It will will boot into safe mode with no problem. I really don't want to tell my friend that he has to buy a new logic board. IS there anything else this could be or anything else I should rule out first?