PSPICE probe window works with a black background as a default colour and it does not allow the user to choose the background colour. However, in order to change these colours, one has to edit the file name "PSPICEEV". This file is not located in PSPICE folder rather it is located in the windows folder. So here is how you can change the background colour in PSPICE probe window.

1. Search for PSPICEEV.ini file in windows folder. [Save a backup]
2. Right click on it and open it in PSPICE. [I tried editing it in notepad but saving it gave me errors.
3. Search for background and foreground and swap their values. (Black to white and white to black]
4. Save the file. 
5. Run the simulation