Hi Nerissa.
To start I must tell you that if the hard drive had been damaged (physical damage), then your data may be lost forever, and only using an expensive facility (about $800 or more), you may be able to recover data.
If the hard disk had been tested on different computers , and it does not work, then here are two possibilities:
The Mybook USB/ATA controller board is faulty.
In this case you can simply take apart the enclosure and mount the disk into a new enclosure. WD Mybooks are SATA, but double check the hard disk connector to ensure.
The hard disk inside is faulty.
In this case repair may be expensive. You need to locate a data recovery facility with a 'clean room' , the cost is usually more than $800.
If this happened after a power surge, then the problem is most likely a faulty controller board.
If the hard disk had been at some stage whacked or dropped, then it is usually a drive internal fault, in that case repair will be expensive.
A replacement enclosure will stfrom art about $20 on Ebay or Amazon, and must not necessarily be WD .
Check if your disk is Sata or PATA (IDE) before buying the enclosure.
Replacement is very simple.
The enclosure is just a box, and inside there will be 4 screws (or more) holding the hard disk to chassis and a connector to undo. Once the drive is free, place it into the new enclosure and connect cable and screws.
Here example of 3.5 enclosures:
Sata:
MASSCOOL UHB-381UES Black External Enclosure - RetailAddonics Combo Hard Drive StarTech.com 3.5in Silver USB 2.0 to PATA:
RocketfishTM - 3.5" Hard Drive Enclosure: ElectronicsSabrent ECS-U35K Ultra Slim USB MicroPac EC-525K 3.5"/5.25" Here how the hard drive will sit inside a Rocketfish enclosure, this is a PATA connector hard drive. PATA is the big EIDE connector with 40 pin, the one that used ribbon cable:
Empty enclosure:
Enclosure with Hard drive installed:
Here instead PATA and SATA connector, so that you know what enclosure you will need. I think your drive is PATA, but chek it outbefore purchasing the enclosure.
PATA - IDE
SATA and E-SATA.
If you want you can save the $20/$30 to purchase the enclosure , and have the disk tested at a shop for about same price. A test will cost you about the same price as an enclosure.
Then if the disk is working, you can ask the shop engineer to install it into an enclosure (job will be done a better way), or get back the good disk and mount it inside an enclosure.
In case the disk does not work, it must be sent to a clean room facility.
In that case the cost will be high.
In that case here two links to clean room facility, you can get a free quote.
USA/CA:
Hard Drive Recovery Group | Clean Room Data RecoveryUK/EU:
Data Clinic's data recovery cleanroomLet me know if you have further questions.
Please do not forget to leave feedback.
Regards.