PBG4 will not boot up- many attempted/failed solutions!

Question

I'll preface this with my computers background: It is a 4.5 year old PBG4 running OSX. I used it in school for various projects, photoshop, illustrator, etc. For the past year or so it has basically been used for photos, internet, and basic nothings. I had trouble with the start up a while back and ever since I get really nervous turning it off so I rarely do.
Tonight, I was closing down my windows and one folder window would not close. I left it for quite a while and it was stuck. So I forced it down and attempted to re-start. That was 4 hours ago. Still no start up Earlier in the evening I noticed another strange and possible related error. When my power cord would loosen up the power would drain down to 30 or so minutes and the screen would go black. If I wiggled the cord and touched the mouse pad it would come back on. This has never happen before.
So I've been on this computer researching possible resolutions. I've tried to start on safe mode (holding down Shift), I've tried control + s, control + v, I have also done optioncommand+pr to reset the pram. I have booted off of the install disk and ran the quick hardware check with no problems found and then restarted. I am currently running the extended hardware test (and going to bed). I have tried to boot off of the start up disk but it only takes me to the install window and this is where I have stopped. I've searched around and haven't found an answer as to what installing OSx will do. Will it erase what I have saved and start clean?
I was ironically browsing Black Friday adds just a few hours before this happened and thinking maybe I should get an external hard drive to back my saved .docs, photos, old projects on just incase something like this were to happen!
Oh and a visual of what is happening-- I press power hear a chime with a black screen, a few seconds and the fans start up and the screen turns grey. If I wait a minute or so the screen goes black again and then returns to the grey screen. A few more seconds go by and the broken folder and question mark start to flash. If I have the install disk in and wait another minute or so it will finally catch the disk and start to read it. When I power it down I hold the power button for 10 seconds (I read to do that somewhere tonight) and I even tried to hold it down while starting it which causes it to make an unpleasant loud beep.
I hope someone out there can help with the information I have provided. I should also say (from reading other posts) that this is the correct start up disk. I only have one Mac so no disks to get confused with and I bought it directly from Mac- I am the first and only user/owner of this PBG4.
Lastly, I should mention that I have no idea what any of the above tricks, solutions, or methods mean- I simply followed directions for my symptoms.
Thanks!

Answer 1

Hi, Andrea. The fact that you can start your computer up from an installer disc, run the Apple Hardware Test, and access the Installer (which also means you can access Disk Utility on the installer disc) all indicates that your computer is fundamentally sound, though your hard drive may not be.
Start up from your OSX 10.5 installer DVD — not the one that originally came with your Powerbook, because that contains an older OS version — and choose Disk Utility from the Utilities menu. In the left pane of the DU window, select your hard drive mechanism: the line that shows the drive manufacturer's name and model number. Click the First Aid tab in the right pane of DU's window, and check the drive's SMART status, reported near the bottom of the window.
If SMART status is "Failing," you'll need to replace the hard drive, and after doing so you'll want to see whether your data can be recovered from the old one. Post back for further advice if the drive is reported to be failing.
If SMART status is "Verified," the drive hardware is probably OK, and only its directory needs to be unscrambled. Click the Repair Disk button near the bottom of the Disk Utility window, and wait for the repair process to be carried out. If any problems are reported to have been found and repaired, run the Repair Disk routine repeatedly until no more problems are reported. Then quit Disk Utility and the Installer. Your computer should restart. Immediately hold down the trackpad button while it is restarting, and keep holding it down until the installer DVD pops out of the drive. The computer should start up normally from its hard drive.
Let us know how you fare.