Video Input problem

I just bought a new 24" Dell Monitor for my best computer and moved my older S2340M monitor to my gaming computer a few weeks ago.  I had some problems at first on switching some of my games to the new monitor's display as I was previously using an older Acer monitor with less capacity.  I got almost all my games converted with minimal problems until today when I tried to install Star Wars the Old Republic.  I had previously tried to install SWTOR with my old monitor and then when I switched monitors had tried again with the Dell monitor but it gave me the following message:

  "The current input timing is not supported by the monitor display. Please change your input timing to 1920x1080@60Hz or any other monitor listed timing as per the monitor specifications"

Previously I had this same problem with Marvel Heroes Online but was able to tab out of it and regain my video...and later was able to reinstall Marvel Heroes without a problem.  With the SWTOR it locked up so when I was able to regain use of my computer, I uninstalled the program, and removed all traces of it from my computer.  I then waited a couple of weeks to retry (I even checked the registry to make sure there was no reference to SWTOR there)....so I thought it was safe to reinstall.  My son who had given me this gaming computer had had no problems with SWTOR when he used it.......so I know its not the computer that has the problem and not really the monitor, but it is something in the game coding that is messing up my monitor. I will not attempt to install the game again on my gaming computer but I would like to know how to get my monitor to work again.  (before installing SWTOR I was using it in 1920x1080@60hz mode.....the Acer monitor was in 1600x900@60Hz mode.)  All I want is access to my computer again...as it is now, it loads the computer info and then when it should be loading my backdrop ready for me to enter my pin, it instead loads that error message.  Any help greatly appreciated.  Thanks