iMac becoming too slow, need suggestion to clean & speed up

Dear Advisor, I have been using iMac for two years and found it now runs slower and slower. Which software or procedure do you recommend for clean and speed it up. I am using Mac OS X Version 10.6.8. Any upgrade available or necessary? Thanks.

The only thing that would effect your speed is your HD is nearly full, if so empty your trashes, don't forget iPhoto's trash.

Also giving your Mac more RAM will always help.

Modern OS don't need much more. Check your logs in Console to ensure that that you don't have something asking for help. Also check Activity Monitor to see if there are processes taking CPU cycles.