I have R51e with 15 XGA
I have T42 Flexview 15 sXGA screen.

Is it possible to put SXGA screen to R51E and to work with XGA resolution of that screen?

R51e has a limited version of Intel graphics, and does NOT support anything else other than XGA.
It will not work with an SXGA+ or UXGA LCD.

Sorry for bringing up such an old thread, but AFAIK the R51e doesn't use Intel graphics. It's a strange animal with its integrated, but ATI-based graphics solution... (Thinkwiki states it's Radeon Mobility Xpress X200, a graphics with integrated memory.)