If you deleted your key-file by mistake, then to restore the key file send description of the problem, information about the place and date of purchase and the LICENSE NUMBER (0XXX-000XXX-000XXXX) / number of the key file (000XXXXX.key) to:
Kaspersky Lab's Partner if you purchased the program from the Kaspersky Lab's official partner.
Kaspersky Lab Tech Support by filling in the HelpDesk form if you purchased the program in a shop/ E-Store