Your computer could not be verified Mac App Store and FaceTime

Question

Hi All
I've been trying through several forums for a long time to find a solution for my problem before giving up, I'll go down to the point:
I have an iMac Intel 20" early 2008 (I can provide more detailed specs when required). I am using Mac OSX Lion installed from a usb and prior used Snow Leopard. They problem has been consistent thru all versions, same symptoms, same all.
1. Whenever I try to login to Mac App Store I get the famous: "your computer could not be verified, please contact support for assistance". FaceTime also does not login, promptying a "server error, try later".
2. Contacted support, and after 16 emails back and forth all I was told at the end was: "I am able to log in into your mac app store account from this side after resetting your account,is there anything I can do for you today".... (!!!!????)
3. There has been a problem parallel to that, and although I am not sure they are related anyhow I need to point it out. My ethernet port stopped working and there is no way to create any connection through it. I can still use wireless quite well (reason why I still keep my machine). After sending the machine to repairs, diagnose was that it could be a problem on the logic board and to fix it may require to replace LB entirely. So I decided not to go for it and keep the machine only with wireless connection.
So I have tried every single solution found (so far...) on google and forums to no avail: a) deleting .plist, b) resetting network configs and creating new locations, c) resetting PRAMs (not sure if it solve anything, but tried anyway) and others. The problem still persists with the same symptoms.
I can login into iTunes store and buy applications from computer, iPhone and iPad, which makes me think that my credentials are valid, alas, I logged into this forum using them.
I also tried creating a new account at App Store, when I request it through the Application, the "little fan that advises you to wait" appears, but suddenly dissapear with no warning or message at all (!!!!????). It is like you never requested anything in first place.
Obviously I can still use my machine for internet and stuff, but my ability to purchase/use any Apple software is seriously restricted. I cannot purchase any software anymore if AppStore is going to be the main way to acquire it (which I think it will).
So, my big questions are:
1) Is this hardware problem (ethernet, logic board, connection ports) remotely related to the machine authentication process when using MacApp Store and FaceTime through Apple?
2) Is there a way to fix this through software, before I consider replacing the machine? (Please take into account that I have already tried TS1811, deleting .plist files, resetting network, creating new locations from scratch... I basically searched thoroughly on google, forums and tips and tried all reasonable found recommendations before posting).
Thanks in advance.

Answer 1

Thanks Livia and Huevoos (eggs??) for your interest in this post.
In a nutshell, I haven't been able to solve this. I gave up on Apple support after they proved useless.
As Huevoos suggested, and I confirmed it time and again after browsing thru endless forums, it seems that the user validation routine for the Mac App Store is done by looking into your network settings, which in my case are either incomplete or erroneous due to the broken-down ethernet. (I am still waiting for somebody more experienced in this forum to contradict or explain this).
So, because I still have wireless connection, I can use my machine for day-to-day chores, have not been able to purchase anything up to this date in the Mac App Store though. I'm waiting for either a software update that could correct this (Mountain Lion??? there's no guarantee only hope) or the moment when my machine will need to be replaced by a new one with a functional ethernet.
I'm sorry I can't be of more help. But I'm pretty much in the same situation as you guys.
Live long and prosper.
Brt1618