If you are running Windows XP on your computer, changing to the United States International Keyboard is a little more complicated than with
Windows '98. However, it is well worth the effort!
Instructions for Windows '98 are from Microsoft support.
Accessing the accented characters is quite easy because the characters for acute, grave, and circumflex accents, the apostrophe, quotation marks and tildes have now been made into "dead" keys, which means that nothing happens immediately upon pressing the apostrophe key or another accent key. If the next key pressed is a vowel, an accented vowel will appear. For an accented a (á), for example, just type the apostrophe, then the a; for an accented e (é), type the apostrophe, then the e. For an è, type the backward apostrophe ` then the e: è. An i with a circumflex is created by typing the circumflex (shift 6: ^) then the i: î. This also works with the double quote (") for the umlaut (dieresis/diaeresis) and the tilde (ñ, ã). If you just want to type an apostrophe or quotation marks, hit that key, then the next letter or the space bar.
For the Spanish upsidedown question mark and exclamation point: type right ALT+/ to get ¿ and type right ALT+1 to get ¡. This is easy to remember because you are using the right alt key plus the keys which have the ! and ?.
This is so much easier than the ASCII Numbers that you will be happy you spent the time to change the keyboard. The instructions look complicated, but they are not when you see the boxes come up. Print them out and follow along.
For Windows '98, see the instructions at Microsoft support.