To type accented letters and other symbols on Windows you can use the numeric codes listed below. These should work in any program.
How it works:
To type a lower case letter with an acute accent on it (á é í ó ú) you can:
Hold down the accent key plus the letter:
Apostrophe (') + letter (a,e,i,o,u) = acute accent (á,é,í,ó,ú)
Slant apostrophe (`) + letter (a,e,i,o,u) = grave accent (à,è,ì,ò,ù)
Quote marks (") + letter (a,e,i,o,u) = umlaut (ä,ë,ï,ö,ü)
Circumflex (^) + letter (a,e,i,o,u)= circumflex (â,ê,î,ô,û)
Note: you have to switch your keyboard layout to United States-International for this method to work. See http://www.lrc.salemstate.edu/aske/accents.htm for details of how to do this.
You can also assign requently-used letters to particular key combinations.
Orthographic diacritics and multilingual computing
Typing International Accent Marks and Diacriticals
Free keyboard layout for typing many European languages and Japanese rōmaji
Character finder - a site where you can find out which accented letters or other characters are used in which language(s), and other useful information about characters, fonts and unicode: http://transliteration.eki.ee/
If you need to type in many different languages, the Q International Keyboard can help. It enables you to type almost any language that uses the Latin, Cyrillic or Greek alphabets, and is free.