I have 2005 professional package ( not student version ) i can not afford a newer version.

The 2017 is very slow, i have very old computers, without internet i doubt the 2017 will work ?,

i tryd it on a fast computer, it takes ages to boot, even on a fast computer, i like to click a cpp file and instant read it.

I see there is a visual studio 2008 upgrade package available.

Is that for upgrade my 2005 to 2008 version ?

Nope, that's probably a service pack or something like that.

VS2017 requires internet access to download the selected packages and free activation with any Microsoft account. After the license is active, you can sign out if you want. You can use it offline without major issues. Account sign in is required to active the free license, to upload anonymous telemetry IDE usage (which can be opt-out), and to sync the IDE settings between different systems.