I would kill them.
The IExplore could be hung processes that didn't get cleared, typical with Internet Explorer. BTW, why are you using Internet Explorer? Try out Mozilla, Firebird, Opera or anything but IE. Here's the reason: IE is built on Activex technology which is dangerous and the #1 for spyware to get loaded onto your machine. To prove this I scanned my system for spyware it was clean. I visited one (1) site using Internet Explorer. After I closed the browser and did a scan I now had 125 different spyware programs installed on my machine. ALL without my knowledge or consent!!!
It depends. There are some virus that masquerade as rundll. You may want to get your PC scanned for viruses at TrendMicro you can get a virus scan online. Also get and run Adaware (lavasoft.de) and Spybot Search and Destroy.
The real rundll is a .dll which has tons of hooks to run different 'programs' such as shutdown dialogs, etc.