Can We Install 2 version of corel on a system?

hello everyone

Can we install coreldraw x5 as well as x6 on a system & use them one by one?

You can install two versions and they will largely work independently because each has its own default path, data and registry keys. In this respect CorelDraw is better than many other programs which try to throw both versions in one place.

You will be able to use both versions for most things, but there are some things to remember ... those I can think of offhand ...

The version you install last will be the one that performs functions that windows is incapable of distinguishing. For example, all .CDR files will be associated with the version you installed last.
You can't teach an old dog new tricks. So, if you install the earlier version last, then you will not see thumbnails for the later version in windows explorer -- unless you manually install corel's Windows Shell Extension for the later version -- which should be able to display thumbnails for both versions.
The default editor for CorelDraw bitmaps will be the same photopaint for both versions of Coreldraw (which will also be the latest version you installed, unless you change the file associations). Whatever you do, you cannot expect Coreldraw X6 bitmaps to open in X6 photopaint and the earlier version Coreldraw bitmaps to open in the earlier version photopaint. Windows OLE has no way of making that happen.
If your default bitmap editor is the 64 bit version of X6, then you may be unable to edit bitmaps from CorelDraw X5. X5 disables the edit capability if it thinks photopaint is not installed -- but cannot recognise the 64 bit version so treats it as uninstalled.