Hi Guys, My macbook is driving me insane now. Just recently, my macbook has occasionally flickering screen and freezes after that. Yesterday, when I was watching youtube on fullscreen, it first has flickering screen, then freezes. So I hard booted it pressing the power button. Then, when I try to restart it, it won't boot pass the apple logo no matter what. Here's my macbook spec 2007 Summer Macbook Pro 15" Snow Leopard 10.6 OS X I cracked my screen once, and got a replacement, don't know if that matters. I've tried the following: Safe mood reboot, the progress bar goes about half, then disappears and stalls again. Booted in verbose mode but it gives a warning message: 'com.apple.driver. internalmodemsupport declares no kernel dependencies; using com.apple.kernal.6.0'. Booted in Single user mood, and typed fsck for disk repair. After checking said the volume Macintosh HD appears to be ok. But still won't boot pass the apple logo after restart. Boot with installation disk pressing C at startup. Success after a few try: Opened Disk Utility and did disk repair (no problem found). Reinstalled Snow Leopard OS X 10.6. This time it booted with Finder and everything for a short while, then the screen flicker and freezes again (before I can backup anything!). Then, I can't reboot pass the apple logo again. When I try to reinstall Leopard OS X 10.5 with installation disk, the macbook seems to try to read the disk, but won't boot. I've got a CD stuck in the optical drive now. I've tried everything I can find online short of opening it up and send it into the oven for baking! I pray it's not a hardware problem, coz I'm no good at that. (QAQ~~~) Please help me! Thank you very, very, very much!!! ps. this is my first post. please let me know if I have missed anything.