it sounds like you may have accidently deleted your shaders or moved them to another folder. Try opening a new scene, then the hypershade to make sure it is loading your shaders properly (look for lambert 1).

Then I would have a look through you maya folders to see if you can find your textures. Did you definitely set your project at the start? It may be that you have another project set and your textures are being stored in that project.