My parents have a 2 GHz Intel Core 2 Duo iMac with 1 Gb 667 MHz DDR2 SDRAM running 10.5.8. It runs so slowly it is almost unusable: spinning beach ball is a regular occurrence, but mostly it just lags and takes multiple seconds to respond to simple inputs such as opening mail, Safari etc. They have very modest use requirements - essentially Mail, Safari and a bit of MS Word. I cannot see anything of concern from Disk Utility, Activity Monitor etc. Given that they have no need for anything other than 10.5, I would just like to do a clean install of Leopard to see if this speeds things up. This has the advantage of nothing 'changing' that would confuse them. I have a full Time Machine backup which I would subsequently like to use to restore from, assuming that the clean install resolves things, but I don't want to end up replicating whatever the issue is that is causing the problem. Is it possible post-installation of 10.5 to incrementally retrieve documents, photos, email, apps etc.?