Internet connection problem

[Geoff]

WinXP Pro SP2 using ADSL (broadband) connection. Just about every night
around the same time I lose my broadband connection. A check of Windows
Administrative Tools | Event Viewer | System or Applications gives no log of
any problems. Running the Modem Diagnostics tells me that the modem is
working correctly. After removing the telephone connection and power from
the modem, leaving off for about two mins, I can usually make the broadband
connection again ok. However, sometimes it takes many minutes before the
connection is re-established and sometimes when I try to log into MSN
Messenger I get the message that there is a connectivity problem and the
program allows me to use its MSN Messenger Connection Troubleshooter. I get
ticks(ok) for IP, Default gateway, IE offline setting, Hosts File and proxy
server. BUT a question mark arises against DNS! The message given is: Your
DNS appears unable to resolve IP addresses. Is this message of any
assistance towards pointing to a resolution of this problem? It does not
matter whether the computer has been running for the past 24 hours or
whether it has been turned off when not in use. My ISP is only able to
confirm that the connection has been lost but unable to provide any further
help. Any help would be appreciated. Thanks.

 

[Geoff]

Further to my query - when I have not been browsing the internet for a
while, I get a "not connected to internet, do you want to work offline or
try again" message. (I click Try again and continue browsing no problem).
Where does that message arise from?