First make sure your system meets the minimum requirements. Since it currently does not, it is a waste of effort to investigate further.
RAM is very cheap. I would do myself a favor, were I you, and fill the MoBo with up to 4GB (properly spec'ed). Even if you still fail to meet the requirements for CS4, your existing apps. will love you for it, and life will likely get easier.
I'd look at my HDD's, while in the case and make sure that I had a minimum of 3x 7200RPM HDD's. If you only have one HDD, it's likely filled to near capacity already. You can probably clean some "stuff" off with the additional HDD's and make life better all of the way around.
Boss bought me Adobe Dreamweaver so I could work on the Department's web site... it wouldn't even install on the 512Meg I had, so had to buy more memory to get it to install and run
Not only that, the MINIMUM specifications that Adobe posts really don't allow you to work very well
My current rig (see http://www.pacifier.com/~jtsmith/ADOBE.HTM for specs) is OK for SD work... but when I get to the point of creating an ISO to write to DVD, I just start Encore before I go to bed and 6-8 hours later when I get up the process is done