Logicboard Replaced: OSX REALLY Slow!

So, my iMac died for the third time last week, but I've finally got it back now. Ever since its return it has been extremely slow! Finder, Firefox, what ever... its all slow. Now I've just found out that my Connect360 won't work! When I click on it in System Preferences, I get the Beach Ball and nothing happens!

Is their anything I can do to get my iMac back to its regular self?

iMac Rev. A 1.8Ghz
OSX 10.3.9

Thanks in advance.

 

Nothing there was taking up any more than 10%. I ended Connect360 and restarted it, so that problem is fixed. Now I just need to get this computer running at its normal speed!