We would like to know what size hard drive you have and how much free space is on it.
If you click on your Hard drive icon (should be upper right hand corner of your screen), or the Finder in your Dock...when the window opens it says at the bottom how much Free Space you have on your drive.
If you go to the , click on About This Mac, click on More Info... in that window. The next window says how big your hard drive is under Hardware....click on Serial-ATA.....look under Capacity:
We need to know this cause if a hard drive is too full it slows things down and creates operational difficulties.
Disconnect all peripherals from your computer.
Boot from your install disc & run Repair Disk from the utility menu. To use the Install Mac OS X disc, insert the disc, and restart your computer while holding down the C key as it starts up.
Select your language.
Once on the desktop, select Utility in the menu bar.
Select Disk Utility.
Select the disk or volume in the list of disks and volumes, and then click First Aid.
Click Repair Disk.
Restart your computer when done.
Repair permissions after you reach the desktop-http://support.apple.com/kb/HT2963 and restart your computer.