sandisk provides the free software of secure access and of course supports it. after you purchase the full version you install the software new with all the extra features that it provides and the support comes then from encryptstick direct.
Regardless of the Encryptstick upgade options I would recommend before installing/upgrading Backing up whatever files you put into SecureAccess to your hard drive, or another flash drive.
As for uninstalling SecureAccess if there is no uninstall option simply delete the 3 files and folders on the flash drive that relate to SecureAccesss.
if you encrypted files with the free version of SA then of course you will need to take them out of the vault in order to encrypt them to the full version
2 you can leave the free version of SA but it would lead to confusion with the 2 at the same time