If this is the first time you are connecting the disk then it needs to be set up before it can appear in My Computer.

Go into disk management.
You should see a disk with no drive letters associated with it.

The size may show as a bit less than 160Gb, as the K or binary 1000 is actually 1024 and when you get up to hundreds of gigabytes this makes a difference. The drive manufacturers use the decimal figure which looks bigger.

You will need to set up a partition on the drive, a single primary partition using the full drive is the simplest.

Once that is set up you will need to Format it.
Quick format is adequate.
You do not need to select a drive letter, one will be assigned by the system if you don't.
You should give the partition a name so you can identify it later.

The default should be the NTFS file system. If not, make it so.

Once format is complete the system will identify the drive and it will appear in My Computer.

Please be sure that when you are asked to proceed with formatting you are formatting the correct drive. Formatting WILL delete all data on the Drive.

Before approving any action, it is best to understand what is going on.
Windows help can be valuable in doing this.

I hope this solves your problem.