Hello and welcome to Bleeping Computer.
Since I do not know the creditability of the person who looked at the computer and said they can not fix it, it makes it hard for me to use that knowledge and determine if the person was a qualified technician and gave a qualified analysis that the computer has more problems then just a faulty hard drive.
You could buy a new hard drive only to find out there is a serious issue with the motherboard where the hard drives communications are not getting into the system.
If the hard drive is NOT being detected, there is no disk utility that can fix this, those only work on drives that the BIOS can detect.
Assuming the person who could not fix the problem was not a qualified technician and they could not determine the exact cause of the problem professionally, I would suggest you try these suggestions and lets hope for a positive result.
Please disconnect the AC power cord from the computer before doing anything inside the computer case.
Please place one hand on the computer case before touching anything inside the computer case to neutralize static electricity possibilities.
Disconnect the data cable from the hard drive and plug it back into the port again.
Follow the cable down to the motherboard and disconnect it, plug it back in again in the same port as it was in before. Please make sure it is secured and tight.
There should be a cable coming from the PSU to the hard drive, unplug it and plug it back in again making sure it is tight and secured.
Make sure nothing is out of place and double check everything closely.
When you are confident everything is secured, plug the AC power back into the PSU and pressed the power switch on the computer case.
Press the proper key to enter the BIOS setup utility and make sure the hard drive is detected, there may be an auto detect option in your BIOS, selecting it allows the selection of hard drives and their parameters.
Be sure to save to CMOS by pressing F-10.
Then exit the utility.
Let me know if your hard drive is finally being detected.
Edited by MrBruce1959, 18 October 2011 - 02:08 PM.