-Session Related Q

Hi, at present i have a problem...in which i'm using session for the logged in members and i use Welcome "session variable name" to display welcome message to the user...i also have a guest login....in which the guest has to click links to enter further pages of them no session is registered... so for the guest i'm supposed to display Welcome Guest in the subsequent pages....all i'm doing this checking if the session variable is set....it works really fine in my local system..... whereas in the net it's properly working for the members....for the guest it's displaying Welcome root....it seems some session is being set....i don't know why.....i'm registering session only for members who login using their username and password..... what could be wrong...is it related to php.ini settings in the webserver where i upload the work.....Please note everything works fine in my local system where i develop the programs...the problem i'm getting is from the uploaded page... Please give me a suggestion to solve this........ Thanx in advance Param:-)