|"my cricket wireless will not work on laptop Compaq Presario Modem 56K"|
Of course not. Why would you think it would work with an analog modem?
"Had windows 98 and installed windows XP now I cannot active windows"
If it's a legal copy of XP & you can't activate due to no internet access, call Microsoft & they'll walk you thru manual activation & will supply a a code to enter. Installing XP on an old Win98 system may not have been a good move. Does it have at least 512MB RAM?