Ubuntu Login problem using GUI interface

I have been coming around with this problem from long time and there is no fixed or predefined solution for this. May be its there but its not in my knowledge. Every time I found different reason of this problem and fixed it. So thought to write some of those issue here and there solution.
Since you are not able to login through GUI but you can still login using terminal. Press & [F1-F6] to get terminal and press to get GUI window.
Now here is different issues:

1. Permission of file "/home/user/.ICEAuthority & /home/user/.Xauthority" might have changed. You check file permission using "ls -la ". If write permission is not given to user then change permission to particular user.
Other thing you can do is "sudo chown user.user /home/ -R"

2. Check if "/tmp" directory permission has changed to root only. If read only then changed it to 777.

3. you can try to run this command "sudo /etc/init.d/gdm restart" on terminal. After that run "sudo gdm" and you will get GUI interface to login. Provide user information and login and if you get success then restart the system. Now you can do normal login. some time it works fine for me!!

some other problems are also there but i m not sure whether they are related to above said problem or not. So I am skipping those issue, may be I'll write later :)

PS: all above solution are hit & trial solution based on what problem I have faced.

Top free Open Source Projects for end users

Here i am listing out some free open source software which i am using and i feeling very comfortable with these software.
1. Most wanted browser : Firefox
2. Most featured Email client (GUI) : Thunderbird
3. Another Email client (Desktop edition) : Zimbra
(Others edition like EE , web client, etc also available)



4. VLC media player (Best player for Linux and others too)

5. Best Linux flavour which i feel more stable among other flavour :

Debian (The Universal Operating system)

continued......

Taste of different Linux flavor

These days i am busy with testing different Linux operating system(OS). Its about 2 years since i have not used windows (Black Box).Yes i thinking windows nothing more than black box. I used windows during my B.Tech. That time i know nothing about Linux. I introduced with Linux in my final year when i started my Project. After that my interest move towards Linux and down towards windows. Its because no tools coming for developer. where as in Linux every essential software coming by default and rest are available through repository. I am using fedora from last 2 years. Its because packages are coming with fedora CD/DVD itself . These days i tested another flavor like Centos, Ubuntu, Debian, Kubuntu, Solaris 10. And off course Mac Os also which available in IITM cse lab. Still i am using fedora but i tried just for see how much difference is there in between all these flavors. I got all flavor because all these flavor are easily available on IITM ftp site except Solaris . And Ubuntu repository is here. So installing all software in Ubuntu is not taking more than half an hour. So, now i am using Ubuntu server edition 8.10. I got surprised when i saw different kind of software available through Ubuntu repository. Its amazing to see long list of software. Even some software which even not available on fedora repository. I like gnome desktop either on any flavor but new version of fedora(10) and Ubuntu KDE desktop is really good. But i think its little slower than gnome desktop. I given some ranking to Linux according to my choice :
1: Fedora - Mac OS. :: (9/10 point)
2: Ubuntu/kubuntu - Solaris. :: (8/10 point)
3: Centos. :: (7/10 point)
4: Windows (all flavor). :: (4/10 point)

Yum configuration :
Centos :
Step 1) add "failovermethod=priority" without quote in /etc/yum.repos.d/CentOS-Base.repo with every repository link.

Step 2) add
export http_proxy=http://user:password@proxyip:port/
export ftp_proxy=http://user:password@proxyip:port/
export no_proxy=.domain.com
export HTTP_PROXY=http://user:password@proxyip:port/
export FTP_PROXY=http://user:password@proxyip:port/

in file ~/.bash_profile
Step 3) run on command line "source ~/.bash_profile"
Step 4) yum update
Step 5) yum install pkg-name.

Fedora :
Step 1) sudo rpm --import /etc/pki/rpm-gpg/*

Step 2) for third party repository search "livna" and get the rpm of livna-release-*.rpm

Step 3) Export proxy same as Centos.

Step 4) sudo yum update

Step 5) yum install pkg-name

apt-get configuration :
Ubuntu 8.10 :
Step 1) Add these two line in /etc/apt/apt.conf

Acquire::http::Proxy "http://user:password@proxyip:port/";
Acquire::ftp::Proxy "ftp://user:password@proxyip:port/";
Step 2) You can export

export http_proxy=http://user:password@proxyip:port/
export ftp_proxy=http://user:password@proxyip:port/
export no_proxy=.domain.com
export HTTP_PROXY=http://user:password@proxyip:port/
export FTP_PROXY=http://user:password@proxyip:port/

these lines same as Centos or add in file /home/user/.bashrc