Heres a good idea for making bot registration keys...

1> Make a zip file
2> Edit it with notepad
3> Make your own encryption
4> Encrypt a key and put it in the notepad
5> On the right of they key, Enter the number (1/3)
1 = Valid key
2 = Banned
3 = Self Destruct
6> Save the zip (Now, when you try to run the zip it pops up an error stating its a currupted zip file)
7>Upload it to a site
8> On your bot, when a user enters a key, Have it download the zip file from the site you uploaded it to
9> Open the zip with your bot for database usage
10> Use the split function and decrypt the key
11> Check the other split side, and check what the number is
12> If it is 1 then save the key to the system registration with a 1 on the right, and show the main form, while hiding the registraiton form
13> If it is 2 then add chat that it's banned
14> If it is 3 then save the key to the system registry with a 3 on the right, and end the bot

On startup:
1> get the key it saved from the system registry (First check if there is one)
If theres not, prompt for a key..
Check the number on the right
if it is a 1, Check the key again on the site
if it is a 3, End the bot
If the key is no longer on the site, addchat that it has expired or something, if the key still has a 1 on the right, proceed to the form

(People will have a hard time cracking this, First they will have to know that they have to edit the zip file, then they will have to crack the encryption)

I already have this on my bot, and it works great

You could also add system properties into this, so that one key only works on one person's computer. Or you could just use a botnet/telnet/etc. server or just cgi

People will have no difficulty at all cracking that.

why lock the shed when everything valuble is in the house?

Or you could encrypt critical sections of your exe with a public/private key pair, which is obtainable by sending your bot authorization keycode and file hash to the server, which will return the public key to use to decrypt it (which is btw encrypted with 3des by the windows serial number and drive volume number). Then the exe uses self-modifying code and rewrites random crap all over the place so you'll need a new decryption key next time.

It also self-checksums.