If the following suggestions work, please let me know and you can Accept the answer (and if possible, leave positive feedback). If not, please DO NOT Accept the answer. Instead, let me know and we'll try some more things or I can refer you to another Expert who may be able to help you further.
Before we begin, are you experiencing the "spinning beach ball of death" when you are running a specific program? If so, continue below, but let me know which program's giving you the issues and we'll address it as well.
Because of the structure of Mac OS X, fragmentation is not an issue for Macs, but overfilled hard drives and a lack of scratch space can be. As well as uncleared system cache and too many open applications, especially applications using too much of the allotted memory on your mac.
First of all, I'd consider the following:
1) Is my hard drive large enough?
2) Do I have enough RAM for my productivity?
3) Can I delete old and unused files on my computer? Or at least archive them off to external drives and/or DVDs?
4) Is my mac able to handle the operations I am requesting from it?
5) Is my mac able to handle the Mac OS X I have loaded?
6) Is my Mac OS X up to date?
Freeing up space on the computer is an easy way to bump your productivity and speed as well as adding more Memory. Also, if your mac is an older mac, it's possible that the processing speed is too slow for the applications you are running (or the tasks they are performing). This you would have to decide based on the minimum requirements for your applications that you use most. Next, it's also possible that the Mac OS X that you are running has surpassed the abilities of your mac. If you are using an older G4, then Leopard may run much slower than Tiger would, even though Leopard says it is suited for the machine. This is something to consider.
Next, it's also a good idea to confirm that your programs and Mac OS X are up to date. BUT BEFORE WE DO THAT, I would suggest (not a requirement, but a strong suggestion) you use a program like Carbon Copy Cloner (http://www.bombich.com/
) to create a restorable backup of your Hard Drive to an empty USB External Hard Drive. This free program will make a mirrored copy of your hard drive in it's current state that you can go back to if things go south after the following changes. I do this personally before I perform any kind of install, update or major change to my system. Again, you DO NOT have to do this, but if you have an empty external hard drive, then it is a good idea. Highly recommended, but not required. If you do decide to go this route, let me know and I'll walk you through the procedure before we proceed.
After you have a backup of your hard drive (if you decide to), the next step would be to run Software Update and confirm that your programs are running at the latest version possible. This can be found under the apple menu. Make sure you have a stable internet connection and a stable power source (don't attempt this while running on battery power on a laptop for example).
Next, I would suggest you run some general maintenance on the computer. It is an obvious square-one approach. This is going to be a long post so I suggest printing it out for your reference.
First let's reset the PRAM on the computer.
1) Shut down the computer.
2) While the computer is shut down, locate these keys: command (has an apple on it), option (sometimes called alt), P, and R.
3) Turn the computer on, then press and hold Command-Option-P-R before the gray screen appears.
4) Hold these keys down until you hear the startup sound a total of 3 times.
5) Release the keys.
Next, let's try a Safe Boot. This will perform several clean up procedures that may be affecting the machine's performance and startup.
1) Shut down your computer completely.
2) Start up the computer and immediately after the startup chime, press and hold the Shift key
3) Once the gray Apple and progress indicator appear, release the Shift key
4) Note: Startup will likely take substantially longer than normal (20 - 30 minutes is not unheard of)
5) In Mac OS 10.4 or later, you will have to login to your account, even if it normally does so automatically.
6) Shut down the computer.
Now let's check / repair the disk permissions. Although this doesn't fix all problems it is a great way to start when working on a machine, besides it often cleans up any other smaller problems you may or may not be experiencing.
1) Restart the machine.
2) Before you have opened any programs, go to Applications / Utilities / Disk Utility.
3) Run the "Repair Permissions" after selecting your Hard Drive from the list on the left.
4) Restart the computer
Next step would be to run Disk Repair from the Mac OS X Install Disks.
1) Insert the Mac OS X install disk.
2) Shut down the computer.
3) Start the machine while holding the C key immediately after pressing the power button (Don't let go of the "C" until it starts from the disk or locks up). If you have to choose, select the Installation disk as the startup.
4) When it starts, a screen should appear asking you to "Choose your language."
NOTE: If you get the login screen instead of the "Choose your language" screen, then the mac DID NOT boot up off of the Install Disk. In this case, try shutting down the computer. Then restarting while holding down the "option" key until the Startup manager appears (http://support.apple.com/kb/HT1310
). When it does, click on the Install Disk as the startup volume.
5) Select your language, then DO NOT continue the Installation process.
6) Just go to the Utility menu in the top menu bar. Choose the "Disk Utility" program.
7) Run Disk Utilities. Select your hard drive in the column on the left and "Verify" the Hard Drive.
8) Repair any errors that it may find by next choosing the "Repair" button.
9) When finished quit the program and restart the computer normally.
Next, let's confirm you are not running too many programs unnecessarily.
1) Go to System Preferences > Accounts > Login Items
2) Make sure you do not have a lot of unnecessary applications or plug ins automatically loading at startup.
3) Remove whatever is unnecessary. Remember, hiding them is not removing them.
After all of the above, restart and test the computer's performance. If you are still not happy, then there may be a conflict in your user account.
Create a temporary admin account to see if the speed issue is system wide or is user specific.
1) Go to System Preferences / Accounts
2) Create this temporary account by clicking on the + button. Make sure you make it an admin account.
3) You may have to click the "lock" in the bottom left corner first though.
4) Once you have this new account created, log in to it and test your performance.
If the performance is the same, then log back into your original admin and delete the temp account. If the performance was significantly better in the temp admin account, STOP HERE and let me know. We'll consider migrating you to a new admin account.