Exchange 2003 server slowed – inetinfo.exe is using up ALL the Memory.

Today my Exchange 2003 server slowed down immensly due to the inetinfo.exe process using up ALL the Memory. The CPU usage is minimal, but the available physical memory goes down. Another process, store, is using a lot of Memory. S.O. is W2003 SP2. I hope anyone can hold me. Nobody can work in my company.