Make sure the cooling fan has not failed. Open the unit and do some forced cooling. Turn the unit off and allow every thing to cool over night, you may be able to recover your data. Remember the unit will start a check disk to check for errors, so be paitient.
SpinRite is the only utility to use on the SnapOS HD's. This software does not try to inturpet data, works on the controller data. It can fix a lot of HD problems.
If your HD's are over 90% full you will also have problems.
As far as parts eBay and
http://www.northwesttechnical.com/ has some parts. I would take the opertunity to upgrade, once the data is recovered, at least to a 2200.