I know, i know! Bingley!
I presume you copied the æ or the Æ. These where created by using the Alt key and code (which must be typed in on the keypad--not the numbers above the letter board) .
To learn which code, produces which charactrer, use the character map in Windows.
---Start--> Run--> (type in charmap) hit run.
the character map window will open. if you select a character, in the lower right hand corner of the character map, you will find the ALT + #### the number will change with each font and each character.
I used ALT + 0230 to create my æ.
The character maps are assigned to fonts-- if your home computer doesn't have the same fonts-- it could have ALT + 0230 assigned to an other font-- and you would get an other character!
If you frequently use special characters, you can assign a short cut to the character map, and have it on your desk top all the time.. Or you can memorize the charactor codes you use frequently -- or make up a cheat sheet of frequently used charactors.. What ever works..
Edit: as AnnaS points out-- the above instructions are for Windows based PC's
