guys! i've reboot my pc coz mine shown 'NTLDR is missing. Press Ctrl-Alt-Del to restart'...after repaired it using my XP cd..it can't continue Installing Windows thus showed 'Isass.exe - System Error > An invalid parameter was passed to a service or function.'. Several minutes later 'Fatal error' came up..saying that setup had problems 1) registering the following OLE control DLL > C:\WINDOWS\System32\initpki.dll 2) The signature for Windows XP Home Edition Upgrade is invalid. The error code is 800b0001. Unknown trust provider. 3) Setup failed to install the product catalogs. This is a fatal error. The setup log files should contain more information. help me guys..i juz want my pc go back to normal, use'able again..plzz!