Fix for Software Update
Delete the following files:
- /Home/Library/Preferences/ByHost/com.apple.SoftwareUpdate.xxx.plist where "xxx" is a number.
- /Home/Library/Caches/com.apple.SoftwareUpdate/ (delete entire folder)
Because you are running 10.5.8 there is no downloadable system upgrade. You would need to buy the retail Snow Leopard DVD from Apple's Online Store if you want to upgrade Leopard.
Snow Leopard General requirements
- Mac computer with an Intel processor
- 1GB of memory
- 5GB of available disk space
- DVD drive for installation
- Some features require a compatible Internet service provider; fees may apply.
- Some features require Apple’s MobileMe service; fees and terms apply.