04 Prius ABS problem

My 04 Prius suddenly had a serius brake problem(lost all braking). This I understand to be the talk of all Prius forums, well here is mine. I was driving about 25 MPH when it happened. The ABS,Brake, and a buzzer warning went off. I could bearly stop the car and the braking was causing the wheel to brake suddeny. I was only 1/4 of a mile from the dealer so I made it their. I had a scheduled maintenance for the next day to repaire the A/C (evaporator) so I left it their. They tooke three days to replace the evaporator as they had to remove the whole dash.

The Prius lead technician is now working on the brakes, I saw him working on the car and going threw the trouble shooting with a manual. He seemed a bit at aw as he said "these cars dont give any problems". For now he is switching out relays, and said that if that did not work the manual says to replace the ABS (he said it comes with the pump and all). I am truly concerned as I have only had this used (90,000 miles) 04 Prius for 3 weeks and it was running great until "Boom".

Does any one have any idea what could be the possible cause of this problem?

Please Post.

P.S. I was just trying to save on Gas.