Currently Being ModeratedMay 6, 2012 8:16 PM (in response to rheathj)
Open Activity Monitor, Show:>All Processes, sort on CPU%, see if anything using too much CPU% when this happens, click on Memory tab, do you have many Pageouts?
Open Console in Utilities & see if there are any clues or repeating messages when this happens.
Also, open console in Applications>Utilities, check the system log for the date/time of the last problem for clues.
As far as Apps...