Help please

, I recently tried to update to Vista SP1, but its been giving me this error that flickers on a black screen after restarting.

!! 0xc01a001d !! 37199/89742 (\Registry\Machine\COMPONENTS\DerivedData...)
sorry but how to do the system restore?I lost the cd of vista.it is for Dell inspiron 6400 windows vista Basic.Can you help me urgently please?I need the laptop badly.all my work is on it
___________________________________________________________________