If the Drive works then you should be able to recover your Files fairly easily under some
conditions.
If you had XP Pro installed and where using Encrypted File System then no you can not recover readable Data. A Data Recovery House is required to do this and even then
there are no guarantees.
1) The computer Crashed. Died. Wouldn't go on ever again, and doesn't want to be resurrected. Will the HDD Enclosure still work?
Depends if the HDD works and is correctly setup it should work. External USB enclosures need to have the HDD set correctly before fitting it and the different types of IDE Drive require different Jumpering. A Desktop HDD which is 3.5 inches needs to be set to Master. A NB Drive which is a 2.5 inch Drive needs the jumper removed from the HDD to work correctly.
Any USB Enclosure that you buy should have it's own Power Supply to prevent damaging the HDD inside it with low power from the USB Port.
2) That computer had Windows XP. The new system will be Vista. Will the two talk?
Maybe maybe not. Depends when the XP Machine was Formatted and what type of Partition Table was being used. An old NTFS Partition may not be readable by Vista which has different Security Protocols. A FAT 32 Partition should be able to be read by Vista.
3) If the answer to either (or both) of those is no, and this won't work, what can I do to recover the data, without paying hundreds of dollars finding out at a PC repair shop?
Well if the HDD isn't working you can not do much yourself it's a Job for a Data Recovery House but if the HDD is working and not readable under Vista you can use a Live Linux to transfer data between the Old and new HDD or you will need access to an XP Computer and transfer your Data across to something else so you can copy it to your New Vista Computer.
When this is done you can plug in the Old HDD and go to Disc Management and format the Old HDD up and use it as a Backup Drive. It will then be visible to Vista. But you need to format it on Vista if Vista can not read the Drive and it is working.
Another thing to remember is that the USB External Enclosures are not for Full Time Use they allow the HDD to get too hot and this shortens the life of the Drive considerably. You should only use the drive as often or as much as needed and turn it off when not in use. If you need to have the drive on for long periods of time you need to get a Metal Enclosure with a Fan in it to help keep the drive cool but even with the best enclosure available it's going to get hot. The other thing to remember with External Enclosures is to always place them on a Flat Surface that is not near a ledge or other place where the drive can fall if the leads get snagged. A HDD Enclosure that falls almost always causes the HDD inside it to be destroyed and if it is necessary to recover Data this is much more expensive than it needs to be or should be. Dead HDD's regularly cost well in excess of 40,000.00 Dollars to recover as much Data as possible so if you prevent Physical Damage you are saving yourself money.
Col