@OP - try this if you want (I know this is posted before but I will get you some steps to start with)
- if you have iPhoto: Open the app and delete all the pics you don't need. Then in the menu bar there is an option to delete iPhoto trash (this is a must, as iPhoto has it's own trash)
- if you have iTunes: Open the app and delete everything you don't need. Also, select to delete the files from the HD
- Now, open Document folder and check what is needed and not needed and delete what you don't need
- Open Downloads folder and do the same
- Open Application folder and trash the apps that you don't want. Check for system applications and downloaded applications. If you are not sure write down everything here and we will try to help
- Now, empty trash
- Go to desktop and click on the top-left logo and look for software updates
- Download Onyx and run everything in the automation tab. It might take few minutes but totally worth it.
I would say, in all, you might have to spend 60 minutes or so for a good performing MAC without software update without RAM upgrades.
Let us know if this works for you... good luck...