Hi,
I would suggest you to perform the following steps and check if it resolves the issue.
a) Open the MS Paint file that your picture is in.
b) Find the area where you want to add text.
c) Select the Text tool, represented by the letter A, in the toolbox on your left.
d) Put the cursor on the spot where you want the text to start.
e) Select font style and size from the help box that pops up when you select the tool.
f) Start typing. You will see the text being added as you type. This is a good indicator of how it will look when you are finished.
g) Click outside of the text, and it will be fixed onto your picture. If the spacing, size, or placement is not quite right, scrap it and start over by first selecting "Undo" on the Edit menu, and then starting the process over again.
For any additional information, refer to the article.
Using Paint: http://windows.microsoft.com/en-us/windows7/using-paint