IIS using 99 CPU and large memory usage even with SP2 installed

Hello,

I am having major issues with my IIS and SMTP services. IIS We are

running Windows 2003 Server with SP2 and Exchange Server 2003. Exchange is

just running on our internal network and not used for external email. The

server runs great until I start the SMTP services. Then the CPU usage

bounces around from 5 to 99 percent and the memory usage goes through the

roof, which bogs down the rest of the server. It won't let me stop the SMTP

service and I end up rebooting the server and setting the SMTP service to

manual so that it will stop. We have all Windows updates run and Antivirus

updated and scanned. Any help you could provide will be greatly appreciated.

We also have 1.5GB of RAM.

Thanks,

Tom