Just to explain a touch more:
All your programs and documents and everything else is stored on the hard drive in your machine. It's a physical device with spinning discs, similar to an old record player.
The issue is that it's very slow (in computer terms). So, you have extra memory in your machine, called RAM, which is electronic, and works far faster.
The next issue is that as things (like Windows, or your programs) are loaded from your hard drive to RAM when you start and use your computer, your RAM fills up. Often, you'll have enough RAM to use and keep bits of it free to load extra programs into memory --- you might want to use a music player while typing a letter, for example.
To make sure you can always do things with your computer, most operating systems like Windows keep a bit of your hard drive locked up so that if you run out of RAM, it can fall back on this space. This is called virtual memory. It's slower than RAM, but it might help you if you're using lots of RAM.
So usually, people come on here and say that they've had a low virtual memory warning. This is usually indicative of not having quite enough RAM to store all your data and programs in at any one time, which is why rojash suggests buying more RAM (it's cheap right now), and it's quite easy to fit.
As a quick fix, you can increase the amount of virtual memory you have (i.e., increase the amount of your hard drive that's locked away to be used in case of low RAM emergencies). This is what the Microsoft site instructed you to do. It's just better to get more RAM, and let Windows manage your virtual memory like it did before.