how to remotely connect to another computer over the internet window,can I do it by Remmina Remote desktop client?Can anyone tell me a way out.I'm using Ubuntu 14.04 and the remote desktop is running on WIndows 8
You can use TeamViewer: http://www.teamviewer.com/
It's very easy to install in any Operating System and very easy to connect (you just need to introduce the ID and PIN of the computer you want to control).
Yes you can use
Remmina Remote desktop client
Its one of many available, and you do not need 3rd party software like Team Viewer.
Other apps for that that you can use on ubuntu are:
Remotedesktop Client,2X Client RDP / Remote Desktop
you can also use
rdesktop from terminal
With any of those you do not need anything installed on the windows machine