A clean install is always best, especially when crossing platforms e.g. 32 bit programs and 64 bit applications. Since your computer is only 3 months old, I presume you have Windows 10. (It always helps to list your sysrems specs e.g. Processor, Ram, OS, HDD, etc. when requesting assistance, since every system is different)... Also, which Sonar platform are you using Artist, Studio, Platinum)...
At any rate, you can uninstall the old Dimension Pro and Rapture. The new Rapture will import the old soundbanks and play them.
Always make sure you install vst plugins to the same location. The default location is C:\ Program Files\ Cakewalk\ vst. VST3 plugins are located in C:\ Program Files \ Common Files.
You can delete the redundant vst files and reinstall them if necessary.
Command Center looks for the programs in whatever location you specify in the Settings...