I currently have Arduino IDE software downloaded from http://arduino.cc/en/Main/Software as arduino-0022 and this is functioning very well. OS is Windows XP Home S/P3. I would like to learn and experiment with the open source programming language as detailed in http://www.processing.org/learning/ . these tutorials need the software called processing-1.5.1-windows to be loaded on to the PC, and this looks pretty much the same as the Arduino IDE software noted above. The physical difference seems to be the inclusion of a display window where the results of any programming done in the text editor is displayed. Can both these programs co-exist on the same PC without causing any problems with either one. I suspect that there may be areas like the windows folder which contain common files and loading two similar pieces of software may cause conflict here. If this is indeed the case is there any other way around this problem.
All the Arduino files live under a single directory (there are no Arduino files in WINDOWS or other common directories) as far as I know. So there shouldn't be any compatibility issues - in fact, you can even have different versions of the Arduino files installed at the same time.
Thanks AndyCC, Uploaded and opened Processing 1.5.1 with no problems at all.