how can I fix my bosch vacuum cleaner?

My bosch vacuum cleaner, a 2000 W Pro Pets model, has stopped working suddenly, while I was using it. This happened once before. We have checked the fuse and that's fine. I have emptied the bag but that hasn't fixed the problem. While I was using it I noticed that the suction had diminished quite a bit. There isn't any warning light that I can see. Any ideas?

Lucy
April 2009