1. Reboot in safe mode
Obviously if it runs fine there and will let you shut down or restart, then it's likely there's spyware/virus/etc issues that are affecting her computer running in normal mode. Hardware shouldn't ever prevent you from shutting down (unless your keyboard and mouse don't work).
2. Scan for everything you can
Make sure you have current anti-virus/anti-spyware programs installed and up to date and then do detailed/full scans. If you don't have any installed, or they don't provide current protection, you can download a good program while in safe mode. You'll have to install or run often in normal mode, but there are some web based scanners that'll work in safe mode to try and get it to a working point if it's that far gone.
I recommend Avast!
(antivirus for free, but also paid internet security suite available) and CCleaner
(for better uninstalling of programs and anything from cleaning cookies to fixing registry issues). Obviously uninstalling programs that could be a source of viruses also helps (Limewire and other torrent programs for instance).
3. Recovery Console
It can be useful, but hardly the first thing I'd try. In fact, I'd probably look to back up any important information and then reinstall Windows before bothering with it. Obviously you'd still want to scan any information you back up before putting it back on your fresh Windows install, but you're better off even if you lose some software you had but lost the disk for. That assumes Windows is something you still have the disk for, or you have a recover partition you can install from during the boot process.
Check out the manufacturer's website for more details on that, as it can be different for different computers.
4. Don't fall for Windows Support scams
There are other videos out there similar (particularly ones that a shorter, but I found this one funny), but call a reputable company if you can't handle the steps on your own. Depending on the quality of the computer you need help with, it might be better just to look for a new one if you have to consider paying for support. Most people aren't running a $1000-2000 gaming/editing rig and would be happy with a $300-500 laptop for browsing and email. A repair could cost a couple hundred bucks, so something to think about.