Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
virtual [ˈvəːtjuəl] adj факти́ческий#; (COMPUT, PHYS) виртуа́льный; (in effect)
it's a virtual impossibility э́то практи́чески or факти́чески невозмо́жно
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.