Can not copy paste or move icons on the desktop IMAC 10.5.8.
This could be lots of things. You should define a new user & see if this works on the new user account.
You may want to run these "standard" fixes if the problem persists.
1) Check the amount of free space on your harddrive. You should have a several gigs free.
2) You should run disk utility
Macintosh-HD -> Applications -> Utilities -> Disk Utility
a) verify the disk
b) update your permissions.
3) Try a safe boot.
Shutdown your machine. Hold down the shift key. Poweron. Wait awhile; wait awhile while you harddrive
is being checked.
4) Another way to correct filesystem problems is into single use mode.
This page will tell you how to get into single user mode.
Basically, you hold down the command + s key then powering on your machine. The command key
has a little apple symbol on the lower left. It is between the alt/option key and the space bar.