I m having lot of problems in my newly install ( also in fresh installed copy ) of ubuntu 11.10

whenever i try to download any software the download stuck at certain point always
e.g. teamviewer 14.4 mb, google chrome 26.7 mb.

if i tried
sudo apt-get- upgrade
it will stuck at [waiting for headers]

same happens with
sudo apt-get install mysql-server
install & download...

i can't determine the problem.

i tried switching server from India to main server still the problem continues.....

can someone please solve this problem