Cells with numbers appear blank in formulas

If I open it in my computer, and change cell formatting from right adjusted to General I can see only numbers without decimal places remain right formatted (are real numbers). Numbers with decimal separator are recognized as text (are left adjusted).
May be after

data tab and import from text, and choose delimited, and then choose by comma.

don't push "Finish" (Or OK or whatever it is in your version) button but "Next" and on the next page of import from text creator select Advanced and make sure proper decimal and thousand separators are used.

May be there is a difference between local settings in configuration of present and previous computers. As here, in Poland, decimal separator is coma (not dot) for me it worked just fine Ctrl+H and replace all . into ,).
But ... try playing with the Advanced and decimal/thousands separator.