Try creating another userid & see if problem persists. Could be a bad perference.
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
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) You may want to run applejack to clean up your machine.
5) Run hardware diagnostics. It's good for a sanity check.
*Re: free space on Hard drive:
Capacity 96.3 GB
*Re: Disk Utility
Verify/Repaired Hard Drive
**The above steps did not resolve desktop window movement or highlighting text.
*Re: Create New User ID:
Have not done this. I am not familiar with the steps to create a new ID
*Re; Hardware Diagnostics
Have not done this. Again not sure how. Only other hardware attached to B/W is an HP Printer(unplugged during attempt to isolate trouble ) and an Apple iSight ( same as Printer)
Have not ttemptd to try Apple jack yet
Create new Account
blue apple > system preferences
clicks on accounts icon
click on lock icon if locked.
enter logon password
click on + icon ( left side of screen just above the lock icon )
after creating new account, you need to logout of your current account.
blue apple > log out ... current count name ...
log on to new account. see if problem goes away.
if it has gone away rename finder preference ( may be more than one file not sure )
/Users/ (your short user name ) /Library/Preferences/com.apple.finder.plist