Only you can to decide to install DSS or not. DSS is typically how Dell fixes their mistakes when implementing how the hardware interacts with the OS.
According to Dell:
Desktop System Software (DSS) is a utility that provides critical updates and patches for your operating system. Install the DSS program to gain support for Dell 3.5-inch USB floppy drives, CD-ROM/CD-RW/DVD drives, and USB devices. DSS is necessary for correct operation of your Dell computer. DSS automatically detects your computer and operating system and installs the updates appropriate for your configuration.
Their instructions for a manual XP reinstallation say to install DSS before any other drivers. In cases where somebody forgets to install DSS first, we always tell them to install it in Safe Mode because none of their other hardware drivers are loaded when booting in Safe Mode.
If you decide to install DSS and are concerned, manually set a System Restore point before installing it. That way, you can always revert to the prior state if something goes amiiss, though I've never seen any reports on Dell's forum that installing DSS this way caused any problems.