My 2008 2.8 - V 10.5.7 iMac has started to show the spinning beach ball on screen when I open most things , its only there for a few seconds things just seem to be slower opening than usual , once some thing has opened it runs normally , If I open finder, or an application the beach ball appears , Ive gone through the Verify Disk Permissions, Repair Disk Permissions Etc and all appears to be Ok . I have a 297.77GB Capacity internal HDD with 124 . 93GB Available . I have 4GB RAM installed , and the iMac is left running over night to perform any maintenance . Can any one please advise me what may be causing the beach ball to appear , and how can I get back to how my iMac was .