Thanks for the reply, Sye d'Burns
Actually the thing is really puzzling me, since couple of days ago I gave Morphix LightGui 0.5.4.1 pre-, and, even though thedefault boot options was 1024*768 screen, Morphix booted with 800*600. Then I tried cheat code 1280*1024 - and it worked!! I had a 1280*1024 screen on my tiny 15" Phillips 105E monitor (which got recognized every time)... Note that 1280*1024 resolution doesn't even existwhile I'm under Win98se or WinXpPro...
I had installed working versions of Mandrake 9.1, Fedora Core 3, Vidalinux Desktop OS 1.0.1 beta Download Edition and now I'm writing this post in Vidalinux 1.1, always with the 1024*768 resolution...
Well, now it doesn't even matter since I managed to install Linux on dual boot without screwing up WinXp OS (and I'm quite certain it's because I left Win98se OS)...