ct2k7

Hi, When I boot my inspiron 6400 up, Vista gives me error: "userinit.exe An application has attempted to directly access the hard disk, which cannot be supported. This may cause the application to function incorrectly. Choose Close to terminate the application" After clicking close, I am presented with a blank desktop/ I can enter task manager through ctrl alt del, but there is not text in the window, show it just shows an icon. explorer.exe is not running, but when I try to launch it: "C:\Windows\system32\dwmapi.dll is either not designed to run on Windows or it contains an error. Try installing to program again using the original installation media or contact your systemadministrator or the software vendor for support." Help, I need to do my coursework and need my data very soon.