I turned on my gears xbox today and it was followed by a really loud hum and just a not good sounding sound. Its been on for about 10 min now and the hum is quiet...is my new xbox breaking already??
Shouldn't be any noticeable odd humming sound. If you can take it back for a replacement or refund. Could be a bad inductor, capacitor, or faulty HDD.
return it or call MS for repair
Is the hum coming from the Console fan, Power Brick or the DVD Drive? If you hear it again take note because the console fan and power brick may increase their intensity when in very hot conditions and that is usually normal.