Q: Mac OS X constantly freezing

Try a safe boot.

    Shutdown your machine.  Hold down the shift key.  Poweron.  Wait awhile Wait awhile while you harddrive

      is being checked.

    http://support.apple.com/kb/ht1455

Run disk utility from your dvd.   do disk first aid & repair permissions.

Other options could be the hard drive is bad or the SMC needs to be reset.

Performance problems can be tied to the SMC. See the following link:

http://support.apple.com/kb/HT3964

Disk utility checks indexing, file integrity, and permissions. It doesn't check drive surfaces for bad sectors, and oddly neither does anything in AHT (it actually hardly makes sense, but that's the way it is). Index corruption might cause the problems and with luck disk utility would correct it.

Unfortunately the problem sounds more to me like a hard drive problem, particularly with a system the age of yours. Another possibility could actually be a logic board fault. I'd check out some of the info from the following site:

http://scsc-online.com

I don't think buying a drive testing software package would do you much good because it sounds really like you can't get anything to run anyway. I'd go to the downloads section and get some of the troubleshooting docs related to hard drives.

If you possibly have an external drive that you could boot from, that could help isolate the problems.

Good Luck.

Run you machine for awhile from your startup drive.  See if it freezes.

I suspect disk corruptions.

verify & repair your startup drive

To verify & repair you file system on the startup drive, you will need to run disk utility from you installation DVD.

This article  will tell you how to get to disk utility.  Once in a disk utility, you can go and attempt to recover the disk.

http://support.apple.com/kb/TS1417

To repair your startup drive, you will need to run disk utility from your startup DVD.
Mac OS X 10.4: About the utilities available on the Mac OS X 10.4 Install DVD

http://support.apple.com/kb/HT2055

How to run disk utility from your startup DVD.

1. Insert your  startup DVD  into your reader.  Power down your machine.  Hold down to the c key.  Power on your machine.  This will bootup your startup DVD.
2. This will bring you to a panel asking you for your language.  Pick your language.



 

3. You you come to the Install Mac OS panel.  Do not install.
4. Click on Utilities menu item.  This will give you a pulldown list of utilities.
5. Click on the disk utility.
   
6. You are now in disk utility.  Pick your disk.  Click on repair it should be on the lower right of the panel.
7. Once the repair completes successfully, you should update your permissions.

Boot off an external drive OR the original install media. If it can't handle either of them then the system is having problems. If it can boot and run normally from these then it's probably the internal drive.