Computer has Bootup problems.

Go to this website:

http://scsc-online.com

They make hard drive testing tools and other stuff. In their downloads section they have a big book at the bottom of the page named hard drive troubleshooting. It's a free download. You didn't say what OS you were using but their products only support Leopard (10.5) and newer so they may not be of use to you.

In my own opinion, based on the inforrmation you provided, I would say iit sounds like your logic board is going south or there's some type of intermittent disconnect in the unit somewhare. I say that because of the comment "Sometimes the LCD does not turn on" is usually not the sign of a hard drive problem.

Hello and welcome to the support community,

Which version of the iBook do you own?

G4 12" or 14"

What you need to do is run the Apple Hardware Test (AHT)

You can run it from the original restore disk supplied when the iBook was first purchase.

Memory problem, hard drive problem, it could be either of both problem. With any luck the AHT will pin point on testing what maybe the problem with your iBook. Here is some further information on running AHT

http://support.apple.com/kb/ht1509

If you don't have the restore disk to run AHT, then you can download a copy for Apple here:

http://www.info.apple.com/support/aht.html

You may also wish to try resetting the PMU,

http://support.apple.com/kb/HT1431?viewlocale=en_US&locale=en_US

iFixit.com has a lot of step by step instructions and now videos for some of the units they take apart. It's worth a shot to look at it. I wouldn't assume the logic board needs replacement just yet, but it is a very likely possibility. Some other things I can think of are:

1. re-seat the RAM chips
2. re-seat the Airport Card

Reseating the Airport card isn't easy like it was on an iBook G3. You need to open the unit up to access it, but I've seen such problems occur when the Airport is no connected properly. Disassembling a 12" PowerBook, if that's what you're talking about, is probably one of the most difficult jobs you can do. Replacing the DVD on one of them is a 3 hour job for me and I have a fair amount of experience. Replacing an HD for me on one of them takes me about 30 min. For me, replacing the HD on an iBook is about a 20-30 min job.

If by chance this is one of the 1GHz iBooks, there's a good chance that cable to the drive has come unseated, and there's also a good chance the drive's cable connector is separating from the logic board.

If you could get an external firewire enclosure, one idea might be to try and install the OS onto an external drive and see if it boots properly and the symptoms end. That could at least get the internal HD out of the picture and narrow down the scope of your problems.

The reality of it is, there are a lot of things that can go wrong.

Hello,

Before reaching for the screwdriver, I would first out rule the OS being a fault here.

If the AHT comes back without any faults, then reinstall Mac OS X.

The last two PowerBook's I own which has had the invalid memory access' was due to the OS.

Back up your iBook's files ect.. to an external drive first and then try a fresh install from the restore disk. It may save you a lot of time and money. Make sure you select options when prompted for the install destination. Click format to extended journal, then flow the rest of the install process.

If then you get the same problem on a fresh install of Mac OS X, look at alternative possibilities.

Hello,

When you say the AHT did nothing what do you mean?

Did it not run on your iBook or did all the results come back as 'Passes'?

Did you have the original restore disks supplied with the iBook? (Grey disk, OS X 10.3)

The hard drives found in 14" iBooks are the same as the 12" iBook's both ATA 2.5" drives.

Little confused by what you have said about replacement drives works for one but not the other.

Hello,

Your trying to install Mac OS X 10.4 from the gray install disks? or a black retail disk?

The mac OS X 10.4 your trying to install did that come with your iBook or the PowerBook?

Hello,

So you inserted the gray disk and held down the option key when booting. Once the menu showing the drives came up, you selected AHT? But nothing happened?