It can be done by two way either by installing tamebox60 or by using dosbox-0.74
1) Using tamebox60
download tamebox60.exe and install it.
download qbasic, and just double click on qbasic.exe and start.
then you are ready to go fullscreen.
2) Using dosbox-0.74
Download and install dosbox-0.74, and qbasic.
Install qbasic at location "c:\qbasic"
By default it will get installed in c:\programe files\dosbox-0.74 directory.
Navigate to directory c:\programe files\dosbox-0.74 and open file "DosBox 0-74 Options.bat" in editor,
and add following lines in "[autoexec]" section.
mount c c:\qbasic
NOTE: to get full-scree use Alt+Enter key simultaneously.