Ctl. + Y dont add any border on my computers.
But remember the OP wants to crop postscripts, not bitmaps.
Irfanview lists postscript as an acceptable input format, although
I've never tried it. It may need a plugin.

Irfanview uses GS for PS. But then it is much better to use GV instead.
There you can convert the PS in a editable format of your joyce. In case of
vector graphics I prefer vector graphics too, like emf or wmf or dxf or
simply ai if you have a DTP that accepts this format.

Marte