When copying disks, Ghost doesn't clone the boot track. You'll need to use the "Windows Emergeny Repair Procedure," check Windows Help for details on your Win version. Or if you use a boot manager/dual boot setup, reinstall the boot manager on the new disk.
Here's the step by step: Boot up from CD or floppy. Choose Repair. Choose "Recovery Console." Select the installation to repair and login. Type "fixmbr." Remove the floppy or CD and type "exit." Your system will reboot normally into Windows.