How To open .Dat file

Please Help Me i Downloade Dat File of Quick Heal Ativirus softwers
I Attached Picture Of Dat File

.dat should be text-based file, therefore you should be able to open it with Notepad.
Now, if it contains contains fields of information (fixed width, or data separated by comma, tab, or other character) you should be able to use Excel (and if less than 64536 rows; in that case you can use Access).
Anyway, it mostly depends what you want to do with the file and its data. But first, i would trying with Notepad to have an idea of what's in there.

What do you mean by this attached image? What are you trying to say?

Well a notepad can tell you the contents of the file!

I don't think any software provide you a .dat file & why you want to open this .file? Don't you have the setup file for installing quick heal?

Never open files such files unless you are sure about its contents. :)

Right click the file choose 'OPEN WITH'. You'll get a caution prompt just click 'OPEN WITH' tab. Highlight the circle 'Select program from list' Click OK. Make sure the Box that says 'Always use the selected program to open this kind of file' is UNCHECKED. Choose 'NOTEPAD'