Intermittent Internet Connection (Ethernet) with Studio Laptop and 64 Bit Vista

I am assuming you have only the one PC attached to the Comcast Modem.  You didn't say whether you were using the Wireless LAN or have an Ethernet cable.  Does it fail on both?   If you have been using Ethernet and not the Wireless you need to try each on separately during the failure.  

Have you tried using the Ping command when the internet is not responding?  The ping command is built in to the software and is used to validate point to point communications.  To use it, goto Start, Run; when the Run command line is displayed, type cmd and press the Enter Key.  This will display a small DOS window.  At the flashing Prompt, type ipconfig.  this will tell you what your network address is at both your pc and at the default Gateway address.  You can then type in the DOS window, the Ping and the default gateway address (Example:  Ping 192.168.2.144, Enter).  You should see 4 responses within a second or two telling a valid response from the far end or it will time out telling you the test didn't work.  This may be a help especially when this is an intermitten problem.  Make sure you write all your information down so you can use it again for reference.

Hope that helps.

Jim

I have the same issue, but with a 530s desktop, and so do other owners of new Dells.  See http://www.techsupportforum.com/networking-forum/modems-cable-dsl-satellite/378475-solved-brand-new-computer-but-my-internet-connection-only-works-intermittently-3.html and scroll down to the comment by a Comcast tech.  As with the original poster, I am connected to the Comcast telephony modem (Touchstone) with an ethernet cable.  I am waiting for a wireless router to see if the problem goes away when the connection is through the wireless adapter.  When I first got the computer a few weeks ago, I was connecting through a wireless connection to an AT&T DSL modem/router (2-wire), which seemed to work fine.  I also seem to be able to connect more reliably if I hook up my old Dell laptop running XP to the ethernet cable.  So it seems to be a conflict between the newer Dells running Vista and the Comcast system.  The Pings sometimes work pretty well, but sometimes all fail.  (BTW, something--perhaps the telephony modem--seems to be pinging my computer every 30 seconds or so, because I had to turn off the "wake on directed packet" setting in the network adapter properties to keep it from waking up very shortly after being put to sleep.)  I have Norton Internet Security, not McAfee, and tried fiddling with the settings there without success.  I also disabled the wireless network adapter until my router comes, but that didn't help either.  I am now wondering whether one of the newer Dell offerings (Dell Remote Access, Dell DataSafe Online) may be contributing to the problem.  Can I test this by somehow disabling them rather than uninstalling them?  I really have little interest in either.

I THINK THE NETWORK GURUS AT DELL AND COMCAST NEED TO FIGURE OUT WHERE THE CONFLICT IS AND POST THE SOLUTION NOT ONLY HERE BUT PERHAPS COMMUNICATE IT DIRECTLY TO NEW DELL OWNERS.  I wouldn't like to have to give up on either Dell or Comcast just because they can't solve what is undoubtedly an issue of settings in Vista or a software conflict, or possibly a problem with the Intel network adapter.

More on the above.  Having received no response, I decided to bite the bullet and try a few more things.  First, I disabled Dell DataSafe Online (preventing it from starting up on boot).  That seemed to have no effect.  Then I started Dell Remote Access and chose to uninstall the whole thing, without ever setting it up.  Since then (admittedly for a time measured only in minutes), my Comcast connection has worked perfectly.  Before that, I would have problems almost constantly.  I don't know what would have happened if I had set up Dell Remote Access without any intent of using it.  Maybe it was the fact that I had not set it up that was causing the problem, maybe not.

If things go bad again and Dell Remote Access was not the problem, I will post again.

Steve