There are several ways to accomplish what you are trying to do. However, keep in mind that X Window is not MS Windows and remote connections and executing remote X11 applications are based on completely different concepts. For one, the X Window system is a client/server system, meaning the X Server has to run on the system that is physically attached to the screen you are looking at. In your case, your Desktop PC.
To set the DISPLAY variable and use xhost authentication is completely obsolete and based on a technology that probably isn't used for 20 years or more anymore. Instead, use SSH with X forwarding or VNC. VNC can be a bit more complex since you may have to install a VNC server, client and tunnel it through SSH because of your Firewall.
Instead of VNC you can also you use SSH with X11 forwarding. In this case you need to install some X Server on your PC and configure PuTTy to establish a session with X11 forwarding. There are a few common and free X Server's available for PC, e.g. Xming (free). If you are running on Apple Mac OS X things are even easier since X Windows and VNC are part of the standard software distribution.
Both VNC and SSH have their advantages and disadvantages. Perhaps the easiest solution for you, assuming you are using MS Windows is to download the free version of MobaXterm, which incorporates a X Server and SSH client in a single application and single file. Simply open MobaXterm and type ssh -X oracle@ip_of_linux_server and open your remote X11 applications, e.g. DBCA or ./runInstaller. That's it.
X11 forwarding will automatically mirror the X11 traffic on your remote server to your client. Just make sure you have Xauth installed on your Linux server (yum install xauth). In this case you should NOT set the DISPLAY variable or use Xhost as SSH will take care of it using Xauth.
I am using Hummingbirg Exceed server in my PC, and configured it for my production server. I have seen it work in vmware in Oracle Linux 5.7 64-bit, But unable to do the same in OL6.2. it did not work for vmware also. On the other hand if Exceed was not working why xclock or xterm appear. So is it something related to oracle installation and rpms? or is it related to x-org fonts, because in xclock there is no font. only the clock.
Hasan Al Mamun
Did you just decide to use Exceed or were you using it all along? Please keep in mind that nobody can look over your shoulder from here. So providing details and describing exactly what you do is important. I don't know if I can or even want to help troubleshooting Exceed problems, but you need to provide your configuration details. I have not used Exceed since the last century and only remember that it does not work unless you know exactly what you are doing.
Something to keep in mind when it comes to dealing with systems located in a datacenter is firewall rules. Often times for security purposes access to the datacenter's network will be more restricted. You may want to talk to your local Systems Administrator and see if the ports for X11 are open from the datacenter network to the network your workstation is located on. Hope this is helpful.