I have a computer dual core 3Ghz and 2 GB DDR2 rams.I have installed Windows 7 Ultimate and two hard disks.One hard disk is of capacity 250 GB.The other shows only 111 GB.Both are SATA and connected at motherboard Asus P5GDC-V Deluxe.Now I'm not sure but 111 GB sound strange at me. It must have 135GB or 150GB Hard disk storage capacity. I have open Disk Management and it doesn't show any free part. On my Device Manager it is identified as ST3120026AS ATA Device. Can anyone tell me how to extend the capacity of this hard disk?