Modem Not Resetting??

My installation is WinXP-Pro. After a boot-up, I can connect with my 56k modem, get e-mail and browse the web. However after disconnecting, a subsequent attempt at connection does logon to my ISP’s server. However, e-mail and web browsing are unavailable. I have to “ReStart” Windows to properly connect again.

My suspicion is that the model isn’t being reset properly by WinXP. Is there a remedy for this?