External hard drive backup problem?

[Parum]

First I hope I am posting this in the right place. Ok, my mom bought herself an external hard drive for the purpose of storing GB's of photos. Now I wasn't there when they hooked it up to her PC but my nephew tells me that he clicked on some options and it started doing it's thing for quite a while. Within a few days the PC started acting up an eventually failed to load Windows XP Home Edition. When I checked the external it had the same amount of used space as her hard drive did which leads me to believe that they inadvertently backed up the system to the external.

So a few days go by an my mom gets some so called "PC Tech" to look at it and he says that there's nothing on the external and that she had start from scratch with a new drive and OS. I think he's wrong since as I stated the external has used space equal to the old hard drive. Now why do I question this techs skills? I was told he opened up the PC and proceeded to clean out the dust with a vacuum cleaner! Can you say "Holy ESD Batman?" So anyway what I would like to know is is it possible to either access the info on the external or can I buy her a new hard drive and transfer the data from the external to the new drive and expect it to work like normal?

I have some experience working on PC's but this one is a bit advanced so I need some help. I appreciate all replies and all your help. 

[Linux711]

Well, what happens when you hook up the external to another comp? How do you know that some of the space is used on the drive?

[Parum]

Well when I hook it up to my PC it sees the external and when I right-click and choose properties the contents are equal to the old drive. Matter of fact I was looking at it last night and you CAN access the info and that's obviously a good thing but what I would like to do is to restore the info back to a clean drive, if possible, so that it will be as it was before.

[Linux711]

I don't know exactly what is contained in the backup (whether it's just personal files or program files as well). If it's just personal files, then just let the PC Tech do his thing and reinstall the OS and then copy the contents of the external back to the comp. Or you could ask him to mirror the contents of the external back onto your comp, but you said the system was having problems booting up windows at that point, so there is no guarantee it will work. So if I were you, first ask the tech to try mirroring the drive and if that doesn't work, then do a clean install and copy the personal files back.

[Parum]

Ok thank you Linux711 that would solve that but now what about the original hard drive? Remember I said that it started acting up AFTER the possible backup. I thought about perhaps trying Spotmau and see if that would work to get the drive going again. What do you think? And hey thank you very much for all of your input!