IMac has gotten slow, have CS5

Question

I have an iMac running OSx 10.6.7 with 2.4 GHz Intel Core Duo and 2 GB 667 MHz DDR2 SDRAM
I run CS 5 and iWork, Safari and Firefox and that's about it.  I use CS5 daily and pretty intensively, and reboot during the day thinking it might clear the cache
Anything I can do to improve performance. It takes forever now (this is fairly recent) for thing to open and load and Safari crawls...literally!
Help please, thanks!

Answer 1

Might be a good idea to check the startup disk in case it needs repairing.
Launch Disk Utility  (Applications / Utilities) Select MacintoshHD in the panel on the  left then select the First Aid tab.
Click: Verify Disk  (not Verify Disk Permissions)
If the startup disk needs repairing, follow these instructions. You will need your install disc to make repairs.
Insert your install disk and Restart, holding down the "C" key until grey Apple appears.
Go to Installer menu and launch Disk Utility.
(In Mac OS X 10.4 or later, you must select your language first from the installer menu)
Select your HDD (manufacturer ID) in the left panel.
Select First Aid in the Main panel.
(Check S.M.A.R.T Status of HDD at the bottom of right panel. It should say: Verified)
Click Repair Disk on the bottom right.
If DU reports disk does not need repairs quit DU and restart.
If DU reports errors Repair again and again until DU reports disk is repaired.
When you are finished with DU, from the Menu Bar, select Utilities/Startup Manager.
Select your startup disk and click Restart
While you have the Disk Utility window open, look at the bottom of the window. Where you see Capacity and Available. Make sure there is always 15% free space.