Cry for techie help

So here I am, on a Monday morning, having been roped in to cure the Headmaster's computer, which seems very ill indeed. Alarmingly, I'm the most technical person in the whole GCSE department. And not having worked in IT for four years now (and even then it was often Linux boxes I worked on rather than PCs) I feel quite clueless.

Is anyone bored out there? Do you fancy casting your eyes over the list of symptoms and seeing what you think? There'll be pints in it for helpful people. (Or any professional proofing/editing you should need. Or a piece of calligraphy. Or whatever)

( an unwell Dell )

Edit: With the freaky shit. It's running Service Pack 1, I've increased the virtual memory and there was lots of free space on the disk. I've also persuaded the Head to buy some more memory, goddamnit. But I've just discovered, in the course of trying to burn a CD to save some of the files -

THIS MACHINE DOES NOT CUT AND PASTE.
IT DOES NOT DRAG AND DROP.
Nothing. Not text in Word, not files in My Computer. I've never seen anything like it.
Oh, and it says Windows Installer is not present, so I can't uninstall or reinstall anything at the moment. I presume there's a nice heavy-duty way of doing format c:// without going through Windows Installer? Oh please let there be.