windows 2003 server fsmo roles.

Dear All,

I faced one problem in one week back, in my company we have Domain Controller as well as ADc, but all of suddenly DC goes down. at that time iam tried FSMO roles from DC to ADC , But iam unable to Seize fsmo roles from DC to ADC. Any possiblity even DC completely down FSMo roles Seize from DC to ADC. Pls help me out.