USB ports not working on Dell E-port Plus

Try reseating the keyboard and mouse into the KVM switch. Then try restarting the laptop with the touchpad and keyboard on the laptop.

No dice.  Weird because the video signal from my laptop  my external monitor (via -> E-port Plus ->KVM) fine.  The KVM is an IOGEAR model; the KVM cable to the laptop has one DVI cable and one USB cable...so the mouse & keyboard come through the USB cable.  I have two other compututers that are working just fine.

I can try bypassing the KVM switch but I'll need some adapters:  USB female -> Mini DIN mouse + Mini DIN keyboard.  My thinking is there's something wrong with the USB ports on the side of the E-port plus.

So...the USB adapter is a Y-splitter.

What happens if you plug the USB cable directly into the laptop instead of into the port replicator?

No luck.  My thinking now is I will get a USB to PS2 dongle -- actually USB to two PS2 cables (so a splitter) -- and will plug the PS2 cables into the corresponding Keyboard and Mouse ports on the E-Port replicator.  Weird because the monitor image from the laptop does display on the main monitor connected to the KVM.

Depending upon the type of Dell  e-port replicator you are using some have firmware updates you can install to update the dock itself especially the Dell Docks.  Other than that you can use a utility to clean up the drivers that are tied to the usb ports. What happens when you plug a device in the usb port windows has to install drivers for that device that are tied to that specific usb port.  This is why when you plug in a keyboard or mouse in a new usb port you are not able use the device for a 30 seconds are so as windows has to tie drivers for that usb port for the device that is plugged into it. To prove this theory try swapping your keyboard and mouse you have plugged into your usb ports, you will find neither the mouse or keyboard will work for a while until windows ties these devices to the specific usb ports, it updates the registry so that the devices drivers are tied to the ports.    often when you plug different devices into a specific usb port windows will still save the old device driver info in registry in case you re-plug that old device back into the same usb port, this gives you instant access to the device. What happens when too many devices are plugged into a specific usb port windows gets confused which driver it needs to install to give functionality for the device that is currently plugged into the usb port.  To resolve this issue I use a usb clean up tool that cleans out all the crud that is tied to that particular usb port, it is like starting fresh with no drivers tied to the usb port, unless something is currently plugged into this usb port than the cleaner will just keep this info only.  The tool I use is called usboblivion and can be downloaded from here. https://sourceforge.net/projects/usboblivion/
 This is a handy tool I keep in my tool box, or my diagnostic tool usb stick.  Its a free app and works well to clean up usb crud found in the window registry.  I never ever had problems of reverting the changes it has made in the years since I started using the tool. It is a standalone app or a portable app that does not install on the computer it runs from the executable file. The excutable creates a backup of the registry before it starts, so you can easily restore the registry if you are not happy with the changes made. .  It also give you and option to close explorer and restart the computer, which is recommended so that the obsolete registry keys can be easily removed. Once the boxes are checked let it do it thing. you would be suprized how better the usb ports will work after doing this.

Well that was the suggestion I gave at the start of my post. I told you to reseat the cables, if you would have followed my instructions you would have realized I gave you the solution to begin with. Often the most simple solutions get over looked as they are too obvious and straight forward.