My airbag warning has come on nd speedo isnt working on my pugeot 206?

I just bought a pugeot 206 hdi 2001 and when I bought it the airbag warning was dispalyed it says airbag fault. Does anyone know how to get this off and if its a big problem?

Also today the speedo stopped working! Anybody got any ideas, the needle isnt moving at all!

Not a good buy!