I installed Lyx 1.5.6 on Windows using the standard installer but found that many images became clipped when converting from .emf (Windows metafile) to .eps format. After quite a lot of searching I disscovered that the problem lay in the settings of the newly installed metafile2esp pseudo-printer. In the "Device Settings" section of the printer properties the "Form to Tray Assignment" setting was A4 for both the "Tray" and "Manual" feeds. Setting these two parameters to "Huge" solved the clipping problem.
I am not enough of a Windows expert to be sure, but I think the problem may arise because when it installs a new printer, Windows defaults to the selections that were chosen last time a printer was installed rather than using a fixed set of defaults. Because I had previously installed a real postscript printer, my tray sizes defaulted to A4. This may be entirely the wrong explanation, but I hope that, in any case, this message helps anyone else who experiences the same clipping problem with metafile2eps. Mike