programs are slow and crash with Cisco router connected?

[abaseballfan]

Hi, I just connected a Cisco 831 router up last Friday for our small network of about 10 computers at our company, and the Cisco tech has been great helping me configure this, so our LAN is fine and the WAN is fine including e-mail and all that, so I left Friday thinking great everything works really good, I came in this morning and programs are not wanting to open and some just crash, as soon as I unplug the network cable from the wall by my computer and try the progams again they work fine, if I plug the cable back in they are all messed up again, so I had to connect the Linksys back up again until I can figure out what's going on with this, does anyone know any settings or what I need to put in that would take care of this? I'm lost, thank you.