I was opening some old photos when I got a message that said I had to download an update. Photoshop would not open without this update. I fugured it was some security thing or other and now find that it has upgraded me to a CS6 trial. I don't want it and will NEVER pay a monthly rental for something installed on my hard drive, but it seems to have overwritten the CS4 I had installed.
It's given me the option to uninstall the trial, but am I then going to have to reinstall CS4?
Every version of Photoshop has a different default install path. You can have many version of Photoshop installed on a machine, Each Photoshop version is independent from the others versions of Photoshop. If the CS6 installer overlaid your CS4 installed you must have change where the CS6 installer installed CS6 and had it overlay CS4.
No CS4 update would update CS4 to CS6 and a CS6 Upgrade would leave CS4 intact.