RNAAPP is Remote Network Access Application, a component of Dialup Networking. It doesn't need to be in the startup folder unless your computer is on dialup and "Listens" for phonecalls. If its not running, Dialup Networking brings it up as soon as you start a dialup connection, It will appear in Task Manager after you dial out, and it will stay on as a background item. It can be a resource hog, and it can cause startup and shutdown problems. It'll come up when your modem initiates a call, but once you're connected, its just along for the ride. I'd remove it from Startup, and I'd kill it once I was connected, or at least before I shut down my machine, but that's up to you. Just disable it in Startup, anyway.
That Rundll could be nothing to be concerned about, or it could indicate a Trojan or "Backdoor" on your machine, or maybe a leftover from an otherwise already removed virus. HiJackThis will show what it is. If your connection isn't "Always On", Backdoors aren't much of a worry, unless they "Call home" once you're connected. I notice you have an antivirus, but no firewall. I'd recommend you at least get the free version of ZoneAlarm