Hi mdorais,
Thank you for visiting Microsoft Answers.
It is a problem found with those KVM switches which did not pass the console display's EDID and DDC information to all the systems connected to the KVM switch.
That explains when you switch/select to other channel of connected system, the connected system simply cannot recognize what display had been connected, so end up with setback to system default (normally is 800 x 600).
Windows 7 checks display and display card constantly different from what XP and other operating systems did.
To solve this issue, just replace the KVM switch with those KVM switches supporting FULL TIME/ Active DDC function.
Please check ConnectPRO new UR or PR serial KVM switches which support Active DDC function to all the ports.
Visit this link for more information:
http://www.microsoft.com/whdc/device/display/KVM-Win7.mspx
Regards,
Afzal-Microsoft Support.
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