Internet Intermittently Losing Connection

I have a Dell Studio XPS 435, bought a week ago.  It has had Internet issues from the moment I got it running.  If I do a continual Ping test, when it's working I get a reply from 68.180.206.184.  I get no more than about 20-30 successful pings at max, usually much less.  Then suddenly it will Ping from 96.42.0.135, and then usually time out (even if it doesn't time out, I lose the connection temporarily).  I called Dell Support and paid a one-time service ($140) and they seemed to fix it...although I'm not sure what he did.  24 hours later, it started happening again.  Another subsequent call and he had me reset everything to the factory settings, which didn't work.  I was then told it was my Internet connection.  That CAN'T be because:

A)  Charter Cable came out and tested...everything's fine--the Cable tech seemed to think it was redirecting to the Ethernet card, but he couldn't figure it out

B)  My old computer hooked up to the same modem and cable lines works fine.

C)  It works perfectly fine in Safe Mode (which is how I'm connected now).

I've tried going into MSCONFIG and disabling everything, but I ended up disabling the internet connection as well.  I don't know enough about which services to enable to allow me to keep connected to the Internet.  I'm assuming I should be able to shutdown some service or startup item that's interfering.

Any suggestions on how to fix this would be appreciated. 

Addendum:  After some searching, I have discovered the wrong ping number matches my IPv4 IP address.