How do I upgrade Ubuntu OS from the CD.

[R Wall]

Hi everyone,

I have an old version of Ubuntu installed. When I went to up grade to Ubuntu 
10.04 LTS I found that the Internet connection would drop out and I would 
have to start again. After doing this two times I ordered the CD.

But how do I upgrade Ubuntu OS from the CD without having to set up the 
wireless network connection etc again. I can start the CD and Try or Install 
Ubuntu OS, but Install may overwrite the wireless network etc.

Thanks in advance for your help,

Roderick Wall.