Hit ctrl+alt+delete, that will bring up the Windows Task Manager. Under the processes tab, see if you can find something that matches wildtangent, perhaps wildtangent.exe or it might be something else. If it's not immediately obvious, you might have to do a google search for each process that isn't immediately obvious until you find it. Stop it running by clicking End Process, and then try running it.
If that doesn't work, there's a way we can stop if from working as you start up which is what it'll be doing, but see if the above will work first.