Is it possible to install windows 7 from a pen drive like windows xp and vista? Windows 7 has a totally different way for installation.

Yes of course. I would suggest a quick search for "how to install windows 7 from USB". There are tons of articles and videos posted.

Windows 7 has a totally different way for installation

not true ,it installs in much the same way a Vista.
anyway I think this thread is just a signature spamming thread

Microsoft has a tool just for this. "Windows 7 USB/DVD download tool". IT lets you create a bootable USB from an ISO file. I've used it many times.