I cheated and cut and pasted from a greeting already sent to me , however, it can be done, see instructions below
1. Press and hold down the ALT key while you type the following four number code on the side
number pad.
2. Release the ALT key and the Spanish symbol or letter appears. For example, press and hold the ALT key while you type 0225, release the ALT and you have á.
Continue the same process for the following Spanish accented letters.
Key + # = Symbol
Alt 0225 á 0193 Á
Alt 0233 é 0201 É
Alt 0237 í 0205 Í
Alt 0243 ó 0211 Ó
Alt 0250 ú 0218 Ú
Alt 0161 ¡
Alt 0191 ¿
Alt 0241 ñ 0209 Ñ
Alt 0252 ü 0220 Ü