problem with graphical mode in DOS (command line) in WinXP

I’ve bough new widescreen LCD and since its installation I have problems with my old MS-DOS application under WinXP. These applications use graphic mode in DOS (like edit.exe) and they run neither in window nor in fullscreen. When I start any of them screen just blink and nothing more. If I try to run it from command line it only clear prompt.
I have tried to reinstall drivers for graphic card and monitor and to replace old one but nothing helps. I run WinXP Pro SP2 on GeForce6200.