This page covers more than one screen. To see more of it, click on the down arrow at the bottom-right of the screen, which looks like this: Most web pages go onto more than one screen, as do word processor documents, spreadsheets, and a lot of others. The thing on the right of the screen which you use to see more of the page is called a scroll bar, and moving up and down (or left and right) is called scrolling. Scrolling is a jargon word - a list of common jargon is found in the Glossary to this site.
The underlined and coloured words in this website are links. Click on them to move to a different page, which relates to the word that you clicked on.
Windows is called an operating system (although this probably won't be much help). Without Windows (or a similar operating system), all you would have is DOS, which can only run one program at a time, and is a complete nuisance to use, as you have to type in commands to do anything. So Windows is what allows several programs to run at once, and makes it "visual" rather than command-based. It's difficult to describe exactly what Windows does - basically it keeps everything working. This help guide covers both Windows itself and software that uses Windows to run. You don't really need to know which is which.
When a computer system goes wrong and can no longer be used, it is described as crashing. Windows is notorious for this. Sometimes a small window will appear in the centre of the screen explaining that a program has "caused an illegal operation and must be shut down". This will probably mean you've lost any work you've done in that program since you last saved it, but other programs should be O.K. Sometimes you get a blue screen with white writing, telling you that the system is unstable or something along those lines. Usually the only way of solving this problem is to switch the computer off, using the power button.
Note: this is not really a good idea and should only be done when you cannot Shut Down by clicking on "Start", then "Shut Down...". You will get an annoying message about it next time you switch the computer on.
The reasons for Windows crashing are quite complicated, and require a detailed knowledge of how Windows works to understand. You certainly don't need to know any of this to use Windows.
Usually, a crash is not caused by the user (i.e. by you), so don't assume it's your fault. The best way of dealing with them is to click on O.K. if you can, click on "Start" and "Shut Down..." if you can, and if nothing works, switch off the computer using the power button.
A lot of programs (e.g. Word, Excel, Paint, Notepad) have similar commands for working with documents. These can be found by clicking on the "File" menu near the top-left of the window. The most common ones are: