Thanks for the offers all, I might give TeamViewer another shot if this doesn't work:
http://www.scirra.com/downloads/releases/construct2-r66-2-tryfix4.exe
This build writes a file called waffles.txt to your desktop as you use it. It's a log of various things happening in the engine.
If you could run the original repro with this build, which is:
- Add a global variable
- Add 'on start of layout' - 'set global variable'
- Set the variable you made to 1
- Click Done - this is where it crashes
Once you've done that, send me your waffles.txt (don't paste it on to the forum, it's probably quite long - try a public dropbox folder). This should include some useful extra info.
Note: if you run it a second time, delete waffles.txt first otherwise it will keep adding to the end of the old file, which is probably confusing.
Hopefully by comparing the log file from my working computer to a log file from one of you with the problem the cause can be isolated relatively narrowly. Thanks for the help so far everyone!