1. Don't panic and stay where you are. 2. Offline Backup X:\Windows\System32\spp\store\data.dat and takens.dat 3. Offline export and keep this registry data [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion] "ProductId"="00178-.......................................................... "DigitalProductId"=hex:a4,00............................................................ "DigitalProductId4"=hex:f8,04........................................................................ 4. Offline exprt and keep keep this registry data [HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\ProductOptions] "ProductType"="WinNT" "ProductSuite"=hex(7):54,00...................................................... "ProductPolicy"=hex:80,56,00..................................................................... 5. When an installation got corrupt, just restore the above mentioned things offline and you are well done. PS: This type of key is hardware sensitive.