Hard Disk problem

Well I just bought a new 650GB hard drive and installed it in my desk top computer now the problem is when i click format.... the capacity says 810GB and earlier today it said 590GB and i cant format it gives me this error massage "windows was unable to complete the format" and when i close the format window it says "this disk in (drive I) cannot be formatted"dose anyone know what to do ?

590GB is correct for a 650GB drive. You need to run the manufacturer's diagnostic program on it.

Thanks Loony it worked ;D