Problem with Sony VAIO notebook

I have a sony vaio, with XP and I have a problem with stanby and hibernate mode. I’ve got an error message that said you have a problem with your modem when I tried the stanby mode. First,I disabled the modem on the device manager and I tried the stanby mode again, and the error message has been changed for the com port doesn’t work correctly, so I disabled the com port on device manager, I reboot the computer and surprise the stanby mode and hibernate does work correctly. I must have com port disabled and modem disabled and it’s works correctly. But it’s not a solution. I upgraded the bios for the lastest version, drivers and so on and always same problem.

Would someone know how to solve this problem ?