have you walked her through trying to run starup repair for Vista? It doesn't seem to work as well as windows 7, but it does work sometimes.
1. When the computer boots, just before Windows would load, start tapping the <F8> key.
2. On the next black screen with white text, look for anything that says "startup repair" or the like - I forget the exact verbiage.
3. Click OK or whatever, go through that, it may take a while, so once started, may want to do something else and come back.
If that doesn't work, try <F8> and then safe mode. If she can get into safe mode, then it could be as simple as finding a startup item or a service that is having issues and kill it. Well, actually, if gets to that point, may can use System Restore
- if can't then may need to do the following to turn off/disable some startup items and services:
1. <Windows Key> + <R>, type msconfig and press <Enter>
2. Change the startup type on the first tab to "diagnostic startup"
3. Reboot, and see if Windows boots now, but just with most everything not enabled/turned on.
4. If it does, go back to msconfig and go to the startup tab. Start re-checking items one at a time. Well, she could try more than one, but more likely to get the issue sooner that way, and then have to verify between items. So basically, check one item, reboot, see what happens. If good, go on to the next one until get the black screen. Once verify the problematic startup item or service, always leave that one disabled, and go about your business.
Another thing that could help: Install (if can get to Safe Mode with Networking, at least) CCleaner, run the Cleaner and the Registry Scrub, fix all found items.. run until all items gone (registry) or else only one or two remaining. Could be that the program uninstaller didn't fully complete, so doing this may clear out whatever was left in registry settings.
Of course a full re-install is always best, but there are other options, possibly.
When you say she uninstalled with her disk, what program was she uninstalling? Knowing that could help be more specific with fixes, and you might even find a walk through online for the specific issue.