The external HDD enclosure sounds like a good idea. An infection still present would present much less of a danger on a drive being used as a "slave", since none of the OS files would be loaded, hence there's less danger of a file involving malware "executing".
First though, I'm a little confused why a manufacturer would set up their restore discs without the possibility of a "non-destructive" repair. My god man, even my Emachines does that!
You can try perusing your recovery discs, and then copying and replacing the "sys.config" file or folder. There's no guaranty that this will work, due to the fact there may be "dll" or "dynamic library link" files that have to be installed rather than merely copied.
If you opt to try and copy data from the HDD, be mindfull of everything you're transfering, since lurking among the passive files may be one or more malware executable files, which will install on the other machine if permitted to run.
The virus problem you experienced at the onset of this issue, may have been downloaded from either a P2P network, or a social networking site, and you should have a chat with your daughter about how this came to pass.
As I understand it, there are a couple of times during bootup that you can actually damage Windows if the power is interupted, you may have been unlucky enough to have stumbled upon one of those times.
Why do you say this is a virus or malware removeal problem, just curious.
I get another error when trying to start that says either there was a power disruption at start up or a reset was done while booting up.
I was tyring to figure out if this was a software or hardware problem so I chose hardware!
My best guess is that your problem is with software. Malware removal isn't always 100% effective, and the latter portion of your post suggests corruption af a Windows file.
There certainly are other possibitities. A bad PSU could have interrupted the boot. A bad HDD could have lost or corrupted the Windows file.
But, you said you had a viral infection, and sometimes damage remains after a threat has been removed. Where there's smoke there usually fire, or a reasonable facsimile thereof.
On the other hand these two incidents could be completely unrelated. Your first complaint is absolutely software related, It obviously remains to be seen if the second one is.
With malware, security programs don't always catch everything, and a piece of software may require operator input to run. Hence it happened later is still a software possibility. So, a "Hijack This" log is something worth looking at.
Obviously all of this is moot if you decide to restore the machine.
