Unreliable internet connection/DNS lookup

Hello all,

I've been having quite some problems lately with my internet connection. I'm typing this on my notebook, as I'm unable to load pretty much anything on my desktop at the moment.
I use a wired connection (for obvious reasons), and before you waste your time testing my actual connection: it works fine on all other devices, wired or not (I actually have a router hooked up to the modem, which also works wonders). The desktop, however, refuses to work. I've tried switching to the wireless network (after removing the ethernet cable), to no avail; I've updated the drivers just now, I'm using Google's DNS (which is probably not broken or anything). When it does load a page, though, it's extremely slow and even then, most of the time it loads them only partially. It should be noted that it will begin (kinda) working for a few minutes at random, only to refuse doing anything else for some more time.

I should note that all the time, Windows insists that I am connected to the internet, and will correctly point that I'm not so if I disconnect the wire or powercycle the modem (if the modem loses internet connectivity and is on, it'll also point out that I am disconnected). I have no ideas anymore.

Here's the ipconfig:

Configuraáao de IP do Windows

Nome do host. . . . . . . . . . . . . . . . : Felipe-PC
Sufixo DNS prim†rio . . . . . . . . . . . . :
Tipo de n¢. . . . . . . . . . . . . . . . . : h°brido
Roteamento de IP ativado. . . . . . . . . . : nao
Proxy WINS ativado. . . . . . . . . . . . . : nao

Adaptador de Rede sem Fio Conexao de Rede sem Fio:

Estado da m°dia. . . . . . . . . . . . . . : m°dia desconectada
Sufixo DNS espec°fico de conexao. . . . . . :
Descriáao . . . . . . . . . . . . . . . . . : Atheros AR9287 Wireless Network Adapter
Endereáo F°sico . . . . . . . . . . . . . . : 00-1A-3F-9C-A6-B9
DHCP Habilitado . . . . . . . . . . . . . . : Sim
Configuraáao Autom†tica Habilitada. . . . . : Sim

Adaptador Ethernet Conexao local:

Sufixo DNS espec°fico de conexao. . . . . . :
Descriáao . . . . . . . . . . . . . . . . . : Intel(R) Ethernet Connection I217-V
Endereáo F°sico . . . . . . . . . . . . . . : 74-D0-2B-2C-AB-E1
DHCP Habilitado . . . . . . . . . . . . . . : Sim
Configuraáao Autom†tica Habilitada. . . . . : Sim
Endereáo IPv6 de link local . . . . . . . . : fe80::2980:f18c:1217:3928%11(Preferencial)
Endereáo IPv4. . . . . . . . . . . . . . . : 192.168.0.10(Preferencial)
M†scara de Sub-rede . . . . . . . . . . . . : 255.255.255.0
Concessao Obtida. . . . . . . . . . . . . . : Wednesday, August 20, 2014 3:30:12 PM
Concessao Expira. . . . . . . . . . . . . . : Wednesday, August 20, 2014 4:30:12 PM
Gateway Padrao. . . . . . . . . . . . . . . : 192.168.0.1
Servidor DHCP . . . . . . . . . . . . . . . : 192.168.0.1
IAID de DHCPv6. . . . . . . . . . . . . . . : 242536491
DUID de Cliente DHCPv6. . . . . . . . . . . : 00-01-00-01-1A-BB-A5-AC-74-D0-2B-2C-AB-E1
Servidores DNS. . . . . . . . . . . . . . . : 8.8.8.8
8.8.4.4
NetBIOS em Tcpip. . . . . . . . . . . . . . : Habilitado

Adaptador de t£nel isatap.{82D492F7-F132-4446-8CE3-21E979CE9A4D}:

Estado da m°dia. . . . . . . . . . . . . . : m°dia desconectada
Sufixo DNS espec°fico de conexao. . . . . . :
Descriáao . . . . . . . . . . . . . . . . . : Adaptador do Microsoft ISATAP
Endereáo F°sico . . . . . . . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Habilitado . . . . . . . . . . . . . . : Nao
Configuraáao Autom†tica Habilitada. . . . . : Sim

Adaptador de t£nel Teredo Tunneling Pseudo-Interface:

Estado da m°dia. . . . . . . . . . . . . . : m°dia desconectada
Sufixo DNS espec°fico de conexao. . . . . . :
Descriáao . . . . . . . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface
Endereáo F°sico . . . . . . . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Habilitado . . . . . . . . . . . . . . : Nao
Configuraáao Autom†tica Habilitada. . . . . : Sim

Adaptador de t£nel isatap.{A81DA8B1-8432-45C4-A18C-49EA25258514}:

Estado da m°dia. . . . . . . . . . . . . . : m°dia desconectada
Sufixo DNS espec°fico de conexao. . . . . . :
Descriáao . . . . . . . . . . . . . . . . . : Adaptador do Microsoft ISATAP #3
Endereáo F°sico . . . . . . . . . . . . . . : 00-00-00-00-00-00-00-E0
DHCP Habilitado . . . . . . . . . . . . . . : Nao
Configuraáao Autom†tica Habilitada. . . . . : Sim

EDIT: It seems it's kind of broken. If you need any help translating, don't hesitate to ask.

Hey Josh,

As if it weren't f'd up enough, the computer works wonders on another connection - same ISP, wired and wireless, everything's the same. I could try that next time I'm there, but then again, it might take a little while. Do you have any other ideas?

Thanks,
Felipe

Hey Josh,

Yeah, we're talking about the desktop that has the issue.