We have a small network hooked to comcast via a cable modem (RCA model DCM235). Several days ago our internet connection performance degraded significantly to the point where web pages loaded very slowly on our PCs and laptops. We began to get "This Page Cannot be Displayed" errors in the browsers, and email (Outlook accessing Comcast's POP and SMTP servers) failed giving 0x8004210B errors on SMTP and 0x8004210A on POP3. Powercycling the cable modem restores the performance of the connection temporarily, but only if we leave the modem off for 5 minutes or more. We run a wireless router (Netgear MR314) connected to the modem and a switch (SMC 1016DT) that a Windows2000 server and Windows2000 and XP machines are connected to. Comcast support was of no help - they said "we can see your cable modem, so the problem isn't with our equipment, its with yours."
What should I try to keep from having to reset the cable modem every hour?