Convert EMF to PDF (vector)

LyX can be used to do this, although it may be a little laborious for multiple images. LyX prefers EPS-formatted vector images, so it automatically converts EMF images to EPS, before converting the entire document to PDF.

Alternatively, you could use the metafile2eps.exe tool directly, and then convert the EPS to PDF, without using LyX:

wmf2eps is old and unsupported but might get your data into a form that can more easily be converted to PDF.

At worst maybe you can use Windows XP mode

The new Windows XP Mode lets you run older Windows XP business software right on your Windows 7 desktop.

Designed primarily with small- and medium-sized businesses in mind, Windows XP Mode comes as a separate download and works only with Windows 7 Professional, Ultimate, and Enterprise. Windows XP Mode also requires virtualization software such as Windows Virtual PC. Both are available free on the Microsoft website.