Shizu said:
Can Linux use all the software that are on Window right now?
There is a Windows emulator you can install in Linux that can run many Windows programs with varying degrees of success and performance.
With OpenOffice you have access to all the stuff you get with M$ Office, but at the open-source price (free), and it is compatible with files generated by Office (Word, Excel, etc.). And of course web browsing can be done with Firefox, Opera, and other mutli-platform browsers, as can email. You can do image manipulation with "The GIMP", etc. (In fact, there are Windows versions of all of those, too.)
But if you have certain Windows applications that you have to use, I would find some way to test them under the Linux before making any commitment.
Note also that you can set up a dual-boot system to run either OS (making the choice when you boot up the PC), but of course then you still need to invest in the Windows software. However, that can give you a chance to experiment with Linux without having to have a separate PC for it.