无法在11.10上更新到Ubuntu 12.04

我在将Ubuntu 11.10更新到12.04时遇到问题，我尝试更新所有可能的方式。

我已经从cd下载了Ubuntu 12.04 ...但是在启动升级选项时不会出现...只是：与擦除磁盘一起安装，以及Install-Other。

因此，在等待了5天后，我认为足以为我的西班牙国家更新镜子。即使没有显示对12.04的任何升级，也只是正常的更新...我尝试更改镜像并更改为主服务器，或者运气...在仔细搜索之后....我发现此镜像确实可以进行升级到12.04，并切换到该镜像，升级也没有运气。ftp.halifax.rwth-aachen.de

在这里和那里阅读，并尝试Sudo apt-get update Sudo apt-get dist-upgrade和do-release-upgrade

他们所有人都没有运气....在做发行升级时，我得到：

Checking for a new ubuntu release
Unhandled exception in thread started by <bound method MetaReleaseCore.download of <UpdateManager.Core.MetaRelease.MetaReleaseCore object at 0x7f03a9f09fd0>>
Traceback (most recent call last):
File "/usr/lib/python2.7/dist-packages/UpdateManager/Core/MetaRelease.py", line 261, in download
uri=urllib2.urlopen(req, timeout=20)
File "/usr/lib/python2.7/urllib2.py", line 126, in urlopen
return _opener.open(url, data, timeout)
File "/usr/lib/python2.7/urllib2.py", line 394, in open
response = self._open(req, data)
File "/usr/lib/python2.7/urllib2.py", line 412, in _open
'_open', req)
File "/usr/lib/python2.7/urllib2.py", line 372, in _call_chain
result = func(*args)
File "/usr/lib/python2.7/urllib2.py", line 1201, in http_open
return self.do_open(httplib.HTTPConnection, req)
File "/usr/lib/python2.7/urllib2.py", line 1174, in do_open
r = h.getresponse(buffering=True)
File "/usr/lib/python2.7/httplib.py", line 1027, in getresponse
response.begin()
File "/usr/lib/python2.7/httplib.py", line 407, in begin
version, status, reason = self._read_status()
File "/usr/lib/python2.7/httplib.py", line 365, in _read_status
line = self.fp.readline()
File "/usr/lib/python2.7/socket.py", line 447, in readline
data = self._sock.recv(self._rbufsize)
socket.timeout: timed out
^CTraceback (most recent call last):
File "/usr/bin/do-release-upgrade", line 83, in <module>
time.sleep(0.5)
KeyboardInterrupt

完成jhon建议的操作后，我也无法使用以太网或无线网络。

有什么想法吗？我认为netroot是导致网络崩溃的原因。