>1- Anybody have VFP6 and VFP8 in the same computer ?
> Does it work nice or VFP8 kills VFP 6 ?

They can coexists w/o problem if you install them into separate directories and do not share foxuser.dbf.

>2- Does refox already protects VFP 8 exe ?
>
>3- If I only compile all my VFP 6.0 applications
>into VFP 8.0 will it run OK or do I have to modify them ?

Most likely you'll have to make some modification to the code to get it to work in VFP8. YMMV.