Norton Net Security '20 Key
 

I bought Norton Internet Security 2010 a while back, I've now bought a new PC and wanted to use it on that BUT I can't find the key for it.

Anywhere I can get it? Or use a keygen that'll do the same job?

Don't do it. Norton slows your PC down and keygens will probably not let you get updates anyway.

Any suggestion as to what to use instead? Preferably cost free.

Avast and Comodo should do the trick. Google em.

AVG is also a pretty decent free anti-virus software.