I hope you really didn't toss it out, if so that was like tossing out $40.00 for like 5 minutes worth of work. All you have to do is put the first 19 characters in when installing the game and then guess at the last one (brute force it)!
Here I'll even get you started:
<first 19 characters> A .... nope didn't work
<first 19 characters> B .... nope didn't work
<first 19 characters> C .... nope didn't work
<first 19 characters> D .... nope didn't work
<first 19 characters> E .... nope didn't work
<first 19 characters> F .... nope didn't work
and so on...