I have CS5 Production Premium installed. I purchased a CS5.5 upgrade solely to get a free CS6 as part of a sales promotion. I never installed CS5.5 and Adobe LWS shows I have a serial number for CS6 - Can I now install CS6, w/o unintalling CS5, and do nothing with the CS5.5 upgrade, which I did not install?
There is no need to uninstall CS5 , both the version can co-exist.
Also for installing the CS6 there is no requirement to install CS5.5 first , you can directly install CS6 but you need to keep the Serial number for CS5.5 handy as it will be required at the time of CS6 installation.