problem maintaining net connection on XP

i have a dual boot pc (winME and WinXP) i can log to the net thru a dial up connection on winME with no problems, but when i’m on winXP and connect to the net using the same dial up provider i cant get a continous connection! after about a minute logged on, i get disconnected. my pc is a p4 2.6G 800fsb w/ a standard modem. please if any one has a solution on this problem give me a hand