Programs not responding

I have a constant problem of programs not responding after a while. I am running 10.6.8 and using the following programs: Adobe CS4, Quark 8.5.1 and Extensis Suitcase Fusion 3. Quark and CS4 will not respond at least 1-2 times a day and I will need to force quit. All the programs are compatible with the OS but never had this problem wth OS10.5? Any thoughts would be welcome. thanks