Windows 7: Win7 Can't access IPV4 settings, start firewall service, and more...

Hi!

I'm having some problems with Windows 7 x64 and I searched a lot on Google but I can't find any solution. I hope someone here will be able to help me!
Some weeks ago, I had no internet connection. I checked my other computer and everything was working fine so after a while I tried to set a static IP via the TCP/IP properties and Internet was back.


Since then, the connection status icon in the taskbar always shows that: Click here to see the picture but the Internet connection works well.


Today I decided to investigate to check what was the problem.
I first tried to go in my network card TCP/IP settings but....


Problem #1 : the TCP/IPv4 window doesn't open! I see it for a second and it closes. (Click here to see the picture - when I double click on the selection in blue, the TCP/IP window appear for a second and then disappear...)
So I went on google and tried to understand what is happening. I then tried the Network Troubleshooting (or something like that - my Windows is in french)
But then, I got this problem:


Problem #2 : Diagnostic policy service does not start
What the...?
I Googled again, tried some FixIt stuff that was talking about the Firewall. I checked my firewall service and it was off. I tried to start it and...


Problem #3 : error 1068 the dependency service or group failed to start
I think that this is a major permission problem.



Could someone help me? I don't want to reinstall all my stuff...


If you need more information tell me!


Thanks A LOT.