GPS stopped working

Since today my GPS has stopped working.
Switching GPS on and off works and the GPS symbol in the notification area is visible when starting Maps. But no location is found at all.
Also rebooting did not help and when usung the app "GPS Status" no GPS satelite was found.
Up to yesterday everything worked fine and I did not change anything since then.

I have my Galaxy S since August and the phone is updated to Froyo early November. The phone is not rooted.

It seems a hardware issue to me, but before going back to the shop maybe some of you knows a trick I can still try. (I did not yet try a factory reset, because I do not expect the solution there.)