I have three Dell 4100MP Units in the office and I very impressed with them...but I have one that causes me headaches everytime it is used. The only difference is that this unit is mounted in the ceiling and the remote refuses to work on a regular basis. It will sometimes work to power on and off the unit. Sometimes it will power it on and not off. And sometimes it will not work at all. I have had the remote replaced twice...and I know it works as it powers on the other units. The Projector has been replaced three times now. I am wondering if perhaps the remote is using 2.4Ghz as I have a bluetooth 2.4Ghz keyboard/mouse combo working in the same room. Could this be the issue?