As MVP Roach stated: standard Windows won't run on an ARM chip. So, no you can't swap out the OS for standard/normal Win XP/7/8/etc..
Also I am not sure that Windows RT only supports Apps from the App Store because of its use of the ARM Chip. I thought I read that the reason we need to use Store apps only is that MS has written RT to require apps be signed to run on their RT platform
--that makes them proprietary. (I think there are other ways to write apps for ARM chips that could be applied to Surface if that were changed.)
If you still are running Win 8.0 RT, you could check on XDA developers' website --there are hacks to allow some .exe (x86) architecture apps to run. Not possible for Win RT 8.1 (yet). Here is a link to their site: http: //forum.xda-developers. com/windows-8-rt/rd-general
(delete spaces after colon and period).
Your situation is a bit confusing since there is much advertising (pro and con) that notes the RT
OS does not run standard windows apps because of the way MS has structured the implementation. Maybe trade it in for a pro.. . recoup some/most of your investment., .