Automated system update of x64 Kubuntu 6.10 to 7.04 has messed up my display settings.

Hardware:
 Video card: Radeon x1300 (standard vesa drivers were used).
 Monitor: Acer AL1722 connected on DVI link as primary display.No second monitor(s) attached to card while it has such capability.

Initiall configuration:
 Kubuntu 6.10 for AMD64 with all updates installed.
 I have to admit that Kubuntu 6.10 did detected my LCD parameters properly upon install, 1280x1024 resolution has been setted up automatically.

My actions to cause bug:
 Updater has offered to download system upgrade of 6.10 to 7.04, I agreed and processed with system upgrade.

Result:
 Generally, system is working fine but upon reboot requested by updater the following issue has occurred:
 My LCD parameters are no longer detected by PnP.As well as LCD model is not detected as well while model of my LCD is present in hardware list.
 This caused system to use 640x480 mode and (in System settings -> Monitor & Display ) slider of screen size does not allowed to choose anything but ugly 640x480 only.

Workaround:
 In System settings -> Monitor & Display -> Hardware I'd choosen my monitor model from list manually.This helped and I was able to set up 1280x1024 back, now all works fine.

Probably, PnP parameters detection of monitor has been messed up.