Serial,Activation problem

[nejko]

i have this problem..i have serial for CS3 Extended but when i enter it can't activate

(i must install again..my pc crushed)

[asyluM]

It might sound silly but often I get mixed up between o's and 0's. Make sure you've entered the right character. If that's right:
Have you bought the product?
Or just downloaded it?
If it's downloaded the problem probably lies there.