Hdd wont show up

so youre using like a usb to ide interface to hook it up? what are the jumper pin settings on the back of the drive?

See this page from WD's website for technical details:

http://www.wdc.com/en/products/legacy/Legacy.asp?Model=AC2120

You may not be familiar with the way old HDD units like this were set up in BIOS. Today almost all IDE drives are configured automatically by the BIOS, and they do this by reading certain required info from the HDD unit itself. But the old way was that the BIOS MIGHT be able to read that from the drive, OR you might have to enter the settings manually. To do this you go the the BIOS Setup page where the HDD's are configured and detected. For this particular unit you would set the HDD type to NOT be "Auto", and set its type number to 47 (I think). Then you have to enter the specs on that WD page for Cylinders, Heads, Sectors or Tracks, an possible for Landing Zone and Compensation. This unit does NOT have LBA Support.

Note that the WD page also shows you three diagrams for how to set the unit's jumper for "Single" (Master with no Slave present), "Dual (Master)" (Master with Slave present) and "Dual (Slave)". You need to set this BEFORE installing it according to how you connect it to the IDE port and cable. If this is the only unit on that IDE port, set it to "Single" and connect it to the END of the ribbon cable. If this is the Master device on a port that also has a Slave, set this unit to "Dual(Master)" and connect it to the end. If this is the Slave device on an IDE port that already has a Master device, set this one to "Dual(Slave)" and connect to the ribbon cable's MIDDLE connector.

If you get the drive parameters set right in BIOS Setup it should report to you some form of the drive's name and model number, and the correct capacity of about 125 MB. Then you can hope that Windows will be able to read its data and show you the drive in My Computer.

If the BIOS recognizes it correctly but then Windows keeps starting it and re-starting it, probably Windows is getting read errors and keeps re-trying. This may mean that the HDD has substantial hardware problems, or it might mean that Windows simply cannot understand a bit of the key info at the start of the unit.

Since it is a WD very old unit, check with WD's Tech Support people and ask whether their diagnostic utility package Data LifeGuard, can be used on this model. If so, I recommend you get and use the "for DOS" version of that package from their website. Why? Because it gives you a bootable CD that boots into its own mini-DOS and does NOT depend on any other OS (not even Windows) to read the unit. You already know that Windows can't do that.

The "for DOS" version you download as a .iso file. That means that is is a complete image of what the final CD will be. But what you must do with it is: you need a CD burning utility like Nero that can "burn" an .iso image to a CD-R disk for you. When you have that disk, you place it in your optical drive, reboot and go directly into BIOS Setup and set your Boot Priority Sequence to boot first from the optical unit, then your normal hard drive. SAVE and EXIT from Setup and the machine will boot from the diagnostic CD. It also will start off asking what HDD unit you want to work on. Once you've made that choice it will show you some basic data including SMART info (there may not be any for an HDD this old) and model info, then provide a menu of tests you can do. Run the Short Test first. If it passes that OK, run the Long Test. Neither of these will destroy any old data on the HDD, but they will tell you if the unit has any hardware flaws, and give you a code and description. If you pass both tests OK, then any troubles are strictly errors in the data written on the drive. But considering your description - constant re-tries at reading - I expect there will be hardware problems.

The simple testing tools are not data-destructive. HOWEVER, the tools DO include some that can wipe out all your data on this unit. Generally, if you try to use one of those, you will see a warning about data destruction and can NOT approve proceeding. So watch for such warnings.