I just a new hard drive to replace the old damaged one. I boot the computer up and it gives me the error message "Error: no boot disk has been detected or the disk has failed"
The old drive you had, had the working os on it and was bootable.
The new drive you put in it`s place is raw.
It needs you to install the operating system to the new drive via a Dvd os installation disk.
Or by a usb flash drive that is made bootable with the OS install on it Jenny.
One thing you need to check is whether the HDD is recognized by BIOS.
In case it is not, there's no way you can install OS on it. You need to double check the connection: use different cables and attach it to another SATA port.