I have a problem with an older intel iMac after updating to 10.5.2. After it first starts up the computer is very unresponsive and slow. It lasts for about 3 min after startup and even after this time it is abit slow. I have repaired the disk, permission and reinstalled the combo update. This hasn't helped. The iMac was upgraded from Tiger and has worked perfect with 10.5.1. What should I do to fix this. Would a clean install be best after a time machine backup?