Oh and by the way, sometimes it seems as though I can "connect", but  I still cannnot browse the internet.

I hope you get a good response to this question.  My Dell desktop in my office is connected to the internet, but no applications can access the internet.  The computer indicates that it is connected and is sending and receiving on the internet.  I've turned the firewall off, deleted anti-virus programs, repaired the adapter, replaced the adapter with a Realtec one that also says that it is connected.  I had a version of Microsoft Office that I could not register, so I deleted that.  Computer connected, but cannot browse, receive e-mail with Outlook, update programs, etc.  Every one of them says there is no internet connection, but network places shows a good connection.  Does anyone have any ideas?

I will try the safe mode option and let you know if it is successful.  I know that the problem is not the modem, because I cannot access the internet at home in DE or at school in PA (two different locations and networks).

That definitely limits the problem to the computer.

Does the connection work anywhere at all?  Has it ever worked?

What does ipconfig /all show when you have the network cable plugged in?  If you computer has a wireless network card, is it able to View Available Networks?

Last, but possibly most importantly, do you have firewall software installed?  If so, does it "trust" the network you are trying to connect to?

No, the connection does not work anywhere, but it has worked for an entire year, both plugged in and wirelessly, until just this month.

When it's plugged in, ipconfig/all shows:

Windows IP Configuration

          Host Name ...............................: Jeanee-PC

          Primary Dns Suffix ....................:

          Node Type ...............................: Hybrid

          IP Routing Enabled ..................: No

          WINS Proxy Enabled ................: No

          DNS Suffix Search List ..............: Belkin

Wireless LAN adapter Wireless Network Connection:

          Connnection-specific DNS Suffix: Belkin

          Description ...............................: Dell Wireless 1390 WLAN Mini-Card

          Physical Address ......................: 00-1E-4C-73-62-2C

          DHCP Enabled ..........................: Yes

          Autoconfiguration Enabled .......: Yes

          Link-local IPv6 Address ............: fe80::1569:2da7:f43b:d09a%10(Preferred)

          IPv4 Address ...........................: 192.168.2.5(Preferred)

          Subnet Mask ............................: 255.255.255.0

          Lease Obtained .......................: Saturday, January 24, 2009 12:42:01 PM

          Lease Expires ..........................: Tuesday, March 02, 2145 7:16:24 PM

          Default Gateway ......................: 192.168.2.1

          DHCP Server ............................: 192.168.2.1

          DHCPv6 IAID ............................: 167779916

          DNS Servers .............................: 85.255.112.37

                                                              85.255.112.38

          NetBIOS over Tcpip ................: Enabled

Ethernet adapter Local Area Connection:

          Connection-specific DNS Suffix: Belkin

          Description .............................: Broadcom 440x 10/100 Integrated Controller

          Physical Address ....................: 00-1D-09-B4-BF-A6

          DHCP Enabled ........................: Yes

          Autoconfiguration Enabled .....: Yes

          Link-local IPv6 Address ..........: fe80::9031:9700:55c0:7186%9(Preferred)

          IPv4 Address ..........................: 192.168.2.6(Preferred)

          Subnet Mask ..........................: 255.255.255.0

          Lease Obtained .....................: January 24, 2009 12:46:41 PM

          Lease Expires ........................: Tuesday, March 02, 2145 7:16:24 PM

          Default Gateway ....................: 192.168.2.1

          DHCP Server ..........................: 192.168.2.1

          DHCPv6 IAID ..........................: 201334025

          DNS Servers ...........................: 85.255.112.37

                                                            85.255.112.38

          NetBIOS over Tcpip ................: Enabled

The wireless network card is able to view available networks.  In fact, it seems that it is able to "sucessfully connect" to a network.

I am not sure about the firewall software trusting the network.  I will try to figure this out, but I have not installed any new software or updates and this was sudden.

I have reset WINSOCK and the stacks by the instructions here: http://forums.techguy.org/networking/790709-cant-connect-wireless-dns-configuration.html

When I pinged the ip addresses, everything worked fine until I pinged yahoo.com.  It said "Ping request could not find host yahoo.com"

I also just did windows network diagnostics and it says, "there may be a problem with your Domain Name Server (DNS) configuration"

And also, by the way, I have Windows Vista OS - If that helps at all ...

GOOD LUCK getting an answer on here. Dell will help you for a price. I have had the same problem with my Dell Inspiron 1525. Connected to wireless but cannot browse internet. My Landlord had same problem and it cost her $270.00 for them to do some configuration via remote access. You will not get the answer on here. I would be shocked if you did. I have done all I could think of and all the researching on the net. At this pont I am so frustrated and upset that dell support will not answer this question when so many people have the same issue. So if anyone finds an answer please share as I will if I find one.

JCMT, have you tried flushing the DNS? Open a command prompt and type 'ipconfig /flushdns' (without quotes).