Natively, the CDR and CPT files do not view well, or at all on computers with no Corel installation.For your CDR, you can export to wmf and most people should be able to view. For you CPT file, you can export to tif or jpg if size is an issue. I tend not to send CDR/CPT files to anyone-especially clients, as I don't want them monkeying with the files and cutting me out of the loop.
Exporting as WMF and TIFF also mitigate any font issues between the creating and viewing computers.