So, my power mac g5 was doing that whole calender and clock reset thing and the screen was shutting off. I was told this was because I needed to replace the battery. I'd had it since 2004 when I bought my g5. So today I bought a new battery exactly like the one I was replacing. At first the tower's light would turn on but nothing was happening, but then when I took the battery out and put it in again the tower turned on totally and the chime occured, etc letting me know it was working. But then the screen remained black! It turns on I think because the light on the display lights up, but the screen remains black. What's going on? Please help!