noise when driving ?

i have a vauxhall corsa AUTOMATIC!
when driving slow you can hear a noise which resemble a squeeky sound but not high pitched or strong, as the cars gets faster the noise also gets faster until it then disapperears. It does this all the time, in gear, neutral, rolling forwards,,, everything! its very annoying now! is it a bearing gone??? Is it cam shaft or maybe even drive shaft??? please help with what it could be and how to fix it! thanks