Slackware :: Slackware 13.37 Doesn't Determine Monitor Size Correctly

I have a display problem since updating to Slackware 13.37. Everything was fine on Slackware 13.1, but when I switched to 13.37 some piece of software came up with the wrong monitor size. I have a 1600x900 LCD monitor but the X screen came up as 1024x768 with blackness on either side of it. Under Slackware 13.1 the X screen came up as 1600x900 as it should without any prompting from me; I didn't even have an Xorg.conf file. I tried using the Xorg.conf file which was needed and work for older Slackwares, eg 12.*, but it didn't work. (Saying it didn't work is a gross understatement! That old Xorg.conf completely screwed up mouse, keyboard, and monitor; the screen was flashing and nothing worked. The only way to get control back was to SSH into the machine from my laptop and reboot. Killing the X server via that SSH console did NOT the flashing or get me back to my console login; only reboot worked.)

I find I can get the screen to be the right size manually by going through KDE's "System Settings" --> "Display and Monitor" --> "Size & Orientation", then disabling "LVDS1" and setting VGA1 to 1600x900. The size of my odd-sized monitor is being correctly detected for the "Auto" choice. Upon reboot LVDS1 stays disabled but VGA1 reverts to 1024x768 so I have to do this each time.I've done some search of the on-line literature regarding the error messages I am seeing in the boot log.

People are suggesting changing all kinds of things to alleviate the side effects of the "conflicting" error message above, even modifying GRUB parameters (which won't work for me since I use LILO).So, I have a manual work around which I must do each time I log in. Does someone know how I can get X or KDE to force 1600x900 upon start (while Linux/X/whoever find and fix the problem) or does someone know of a real fix?