Hey,
So, you haven't ever "seen" your new hard drive show up in my computer, although the bios has detected it, and supposedly it is a good working drive. Lets assume all of this is true.
Because you didn't specify what level of experience you have with computers, I'll try to guess; If I am describing too much, please let me know.
What I think your problem is:
The new 320GB Harddrive that you have installed either has not been partitioned, has damaged partition(s), or has hidden/inactive partition(s)
What do partitions have to do with not being able to see your new hard drive in My Computer?:
What you are seeing when your hard drive "shows up" in my computer -the Icon and its name - is not the same as device manager. Instead of representing the presence of hardware, in your case a new hard drive, it actually represents an Active Partition of that drive. So..If for some reason the drive you took out of your Gateway PC has Inactive/Damaged/Corrupt partition(s), it makes sense that you can't see your new 320 in My Computer.
A Simple Resolution:
1. Right click on "My Computer" and choose "Manage". A window will open called Computer Management.
2. Under the "Tree" tab on the left of the window, find the branch called "storage" under that choose "Disk Management".
3. This window will display a list of your hard drives and information about them.
You might be able to figure out what you want to do from here just by getting to Disk Management. If the entire 320GB is labelled "Unpartitioned Space" right click on it and format it. How you divide the drive is up to you. If you do divide the drive into two 160GB partitions, they will show up in My Computer looking like separate drives, and will act as such. Although physically the drive remains unaltered, and in device manager, it will still look the same.
