Custom Addressbook can also run directly from a USB drive. There is no need to explicitely install it on the USB drive, just copy all the files to the USB drive (from the Custom Addressbook program directory on your harddisk or from the downloadable zip package). Then you can start the program by double clicking on its executable.
You might also want Addressbook to store its settings on the USB drive. You can configure this inside the program's settings screen (Menu: Options⁄Settings). If Custom Addressbook finds the file cab.ini inside its program directory it will use this file (instead of the registry).
Please remember that you also need to copy your data file(s) if you have created any. You usually can find the location of your data files (except for the one that is currently open) by looking at the entries inside Menu: File⁄Reopen. You can find the location of the currently open data file inside the program's statusbar.
If Custom Addressbook finds the file addressbooksw_manual.exe inside its program directory, it will use this version of the manual over any other version that you might have installed elsewhere.