Can user install virtual pdf (postscript) printer on Windows without admin rights?
By default (Ghostscript, doPDF...) require the admin right.
May be where is a some way to install virtual printer for user?
Sounds more like a Windows policy than anything else, which is set up by the administrator of the Windows installation.
The current shipping version of Ghostscript includes a signed .inf file, which avoids the problems previously encountered. However, the user must still have rights to add a printer, there's no way to add a printer without having the right to do so.