Computer keeps freezing and very slow

Hi MeggenF!

I have a couple of suggestions for you that should improve your system performance. First, you may want to try resetting the PRAM on your computer and your SMC. More about those two systems and how to reset them can be found in these articles:

About NVRAM and PRAM

http://support.apple.com/kb/HT1379

Intel-based Macs: Resetting the System Management Controller (SMC)

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

You can also create a new Administrator account on your computer, transfer any data that you want to keep into that new administrator account, and then delete your current administrator account in order to fully get rid of any old data left by the previous owner of your computer. More information about doing this can be found in the following articles:

OS X Mountain Lion: Create a new user account

http://support.apple.com/kb/PH11468

OS X Mountain Lion: Share files with others who use your computer

http://support.apple.com/kb/PH10636

Thanks for using the Apple Support Communities!

Cheers,

Braden