Laptops and video splitters

[Zourous]

We have a desktop PC in our hall for the teachers to use with our hall projector. There is a powered video splitter connected to it that outputs the display to the projector and the PC monitor. However, occasionally someone will want to connect their laptop to the projector. When this first happened, I removed the vga cable at the back of the PC and plugged it into the laptops external vga port and did the usual key combination to output to the two sources. Unfortunately this did nothing, I just got a flicker on the laptop screen for a second. To resolve the problem I removed the video splitter out of the equation and it worked fine. So does anyone know if this is normal behaviour when using a video splitter and a laptop? I would prefer to not mess around with cables if I don't need to.

[AceDaz]

I have had this issue before with laptops, one would work fine and then plug another brand of laptop in and it wouldn't play ball. In the end I replaced the splitter with a different one

[pslater]

Have found similar problems a number of times. Am tending to think that the quality/power of a graphics card has alot to answer for when using the same splitter/adapter. Wherever possible now, we are trying to use hdmi/networked projectors. You may also encounter problems if running VGA/VGA over CAT5 parallel to mains power.

[Zourous]

Thanks for your comments, it looks like there is no way to guarantee it will work with any certain splitter so I'll just have to fiddle with cables as and when the need comes up. It can be a show stopper if another tech who doesn't know (or doesn't remember) comes across this situation, so I was just checking if I could make the set-up any more fool proof.