I do not understand why I am very hard to renew my acc.My computer often fail and have to install the program win.But when setup L2tower then.Although I tried to renew my acc before reformatting win the system and install the program again without success.Please guide me?

From my point of view it looks like you:

userId hardwareKey banDate
43250 51e04d35c5da520836209e0c6df02196 2012-10-07 15:53:41
43250 879d8eaabe60f1daf8ababa80ba25eb6 2012-10-07 14:22:15

You got problem because you already banned your key.

It's looks like you banned a 879d8eaabe60f1daf8ababa80ba25eb6 key.
Then created license on 51e04d35c5da520836209e0c6df02196, then banned it, and again created license using on 1.4.1.89 version....

I removed it from a list, but dont know why you didnt read message.

I did the same thing...... I sent you an email for some reason I have done the renew thing before and never had a problem. Oh well, next time I will read the posts a little better... Windows 10 Upgrade frustrations.