I've been trying to fix my macbook for couple days now. I've erased the entire HDD and installed leopard OS on it. I didn't want to install anything on it besides msn since the problem keeps popping up. So basically what happens is safari and msn keeps crashing everytime i start up my mac and try to use them. If it doesn't crash, i get a "you need to restart your computer..." screen. Now its worse... i get a message right when i turn on my computer: panic (cpu0 caller 0x0042F4E3): "Unable to find driver for this platform: \"ACPI\". \n"@/SourceCache/xnu/xnu-1228/iokit/Kernel/IOPlatformExpert.cpp:1378 Debugger called: <panic> Backtrace, Fromat - Frame: Return Address (4 potential args on stack) 0x41573dd8 : 0x12b0e1 (0x4555b4 0x41573e0c 0x133238 0x0) 0x41573e28 : 0x42f4e3 (0x49799c 0x4d77720 0x41573e58 0x4de2600) 0x41573e48 : 0x40d662 (0x4dc0b00 0x4dc0b90 0x1 0x3e80e0) 0x41573ea8 : 0x40f4f7 (0x4dc0b80 0x4dc0b00 0x4de2680 0x0) 0x41573f28 : 0x40ed5b (0x4dc0b80 0x4de2700 0x8 0xffffffff) 0x41573f78 : 0x40d9d7 (0x4dc0b80 0x0 0x41573fac 0x1) 0x41573fc8 : 0x19e2ec (0x4d774c0 0x0 0x1a10b5 0x4dd88b8) Backtrace terminated-invalid frame pointer 0 BSD process name corresponding to current thread: Unknown Mac OS version: Not yet set Kernel version: Darwin Kernel Version 9.0.0: Tue Oct ... So i've tried the apple hardware test before i got this long message and results were ok. macbook is running 2.1ghz core 2 duo, 120 HDD, 4GB ram. I've tried switching the HDD and everytime i boot up, it'll give me a "you need to restart your computer..." screen. I have an appointment at the genius bar on saturday but if i can fix this before saturday it would be great. Any help is appreciated! Thanks!!!