Teresa asks:
What is the main advantage that ScanReg has over System Restore?
These tools have similar functions (they both san save, restore and apply versions of the Windows Registry), and using one over the other depends on your situation and software:
ScanReg: This is a command line utility that allows you to restore earlier versions of the Windows Registry. It's only available for use in Windows 98 and Windows ME.
System Restore: This is included as part of the Windows XP System Tools, and also runs automatically when you boot your PC to Safe Mode.
An advantage that ScanReg has over System Restore is that ScanReg can be run from a "true" command prompt. System Resore can not. The closest you can get for System Restore is documented at this link from Microsoft.