A form to Query and post to a databse

Hi all,
I was wondering if anyone could assist me with creating an .asp page which can check a field in a databse and if correct allow a user to enter in a username and Email?

I have no programmin experience whatsover and have spent the last two days attempting to do this but have had no luck.

If anyone can assist me here it would be so greatly appreciated. If you feel like you do not want to just post the code as you feel you will be doing work for me I understand. If you could maybe post some and leave a little for me to work out on my own maybe? I am looking to develop it myself to then check if another user enters into the field that it has not been entered in already. I feel if i get teh first part done then I should be able to see that and wrk out that part for myself.

Even if its just poinnters or links to some websites that could assist it would be greatly appreciated.

Thanks
Daryl