I assume that the hard drive in the fried system is an IDE drive and that's what the problem is?
Probably the simplest thing to do would be to buy an external disk enclosure that supports IDE drives - you could put the disk into it, hook it up to your computer using USB, and then pull the data off. And then you (or they) could continue to use the drive as an external device if you wanted (great for backups!).
Here's an example of such an enclosure: http://www.newegg.com/Product/Product.aspx?Item=N82E16817145131