What software is need to make complete assembly program?

If you are in school, They will have suggestions but Keil work great. (a href="http://www.keil.com/)" rel="nofollow"http://www.keil.com/)/a also Proview is another but has issues on different versions of Windows. (a href="http://www.google.com/url?sa=t&source=web&cd=7&ved=0CEcQFjAG&url=http%3A%2F%2Fwww.supershareware.com%2Fproview-assembler-free%2F&ei=fRfyTcLvLqHm0QGYr9mMDA&usg=AFQjCNFQkd8p-_YTe6EqUEI5ss4FHthKVQ)" rel="nofollow"http://www.google.com/url?sa=t&source=we…/a