i buy new laptop c 400 i install windows xp and download driver of modem on dell site i download both two driver on site

Conexant By Actiontec MD56ORD V92 MDC Modem                                                         Conexant D480 MDC V.92 Modem                                                                                                                                                 but it cannot install modem. what can i do now also how to check themodel no of modem