WiFi or Ethernet do not work! (need to renew DHCP lease) works 10 seconds

[madominguez7]

I Have a Macbook and the Wi-Fi or connected Ethernet will not work. I renew DHCP lease and the internet works for 10 seconds than I have to renew it again. I have 2 more Macs and they work fine. I have two routers (cable and DSL) and this computer has the same problem with both. Is there a way to solve this?
I have notice that a lot of people have had this problem has anyone resolved this issue.

MacBook, Mac OS X (10.6.8), 2.2 GHz Intel Core 2 Duo 1 GB

So far this is what I have tryed:

Macintosh> Library> Preferences> SystemConfiguration (deleting all documents in this last folder).

-reseting router

-Macbook Software update

-Flush DNS cache using Terminal (dscacheutil -flushcache)

-holding Command+Option+P+R during restart until hearing another chime

-airport on/off

-removed airport and added again from Network Preferences

-Network>Advanced (deleted Preferred Networks and also from Keychains)

 

[oldscribe]

Hi,

A couple if things,

1) How long has this issue been going on.
2) Have you downloaded any video codecs recently.
3) Also try this make a new user account and see if the issue persists. If it does then I would run a hardware test as follows.

Boot off your Install Disk while holding down the *d key*, (not c key), then run the extended Apple Hardware Test, and see if the Airport card passes.

EDIT:

Have you logged on to a public WiFi or friends system recently?