Remot key programing

[Yanzman]

Hi ppl.
I got a problem,with my remote locking key.batterys went flat on it and i didnt use remot locking for a week. changed batterys and now my remot locking wont work,i have to lock and opne my car manualy.
does any one now how to reproram my key but bigest problem is that i have only one key.
car is audi a4 b5 1.8t quattro 2000

(sorry for my bad english)

[Foxmeister]

There are techniques for it if you search....

But when i changed a battery before and it didnt work, i just kept pressing lock and unlock a few times and it started to work straight away again!