I can guess what you're trying to do...
take your text file, make sure it's delimited, and save it with a CSV file extension - or save your excel as a CSV
then use the import data feature on the table righ-click in the tree
I have tried to load the file but the dialog box says that there is no reader for text files...
And also the same issue while impoting .xlsx file the dialog box is not responding..
What dialog box?
You have to SHOW US:
1. WHAT you are doing
2. HOW you are doing it
3. WHAT results you get
4. WHAT results you expected to get
We can't see your file and you provided NO info about what type of file it is, how it was created or what is in it.