While installing Red Hat Deluxe Workstation 7.0 Configuring X Windows and choosing 'test this configuration' resulted in a corrupted screen from that point on unable to read any further instructions. The corruption was/is the standard X background pattern. The video card in question is A NVidia TNT2 based card. The work around is to do the X configuration post install.
I got this too, with a Geforce 256 SDR card. I asked for 1600x1200, and pressed "Test." The test screen came up fine, but when it returned to the installer the screen was corrupted, and only the navigation buttons remained visible, so it was impossible to continue the install. I restarted the install, did the X configuration with the same 1600x1200 resolution but did not test it this time around. After completing the install and firing it up, the display works fine.
Which brand cards do you have? We have tested cards we have based on these chipsets with no problems, but the X server for these chipsets occasionally has issues. It is more an X server problem than installer problem. Brent lets keep note of these reports so we can see if there is a trend of problems.
My card is a guillemot Cougar Maxi Gamer Video edtion. the PCI info is: PCI:*(1:0:0) NVidia Riva Ultra 64 rev 17, Mem @ 0xfd000000/24, 0xf2000000/25 NVidia's driver reports it as such: (--) NVIDIA(0): Chipset: "RIVATNT2 (M64)" This is an AGP card if that makes any difference.
My Geforce 256 is a "Creative CT6962 (AGP)". In case it's useful, the system is a Micron Millenia MAX P3 533, the chipset is VIA Apollo Pro 133A, and the card was the original one that shipped with the system.
Unfortunately the X server for these cards is in a beta state so it is known to have problems. You have already found a workaround for the time being which seems reasonable.