December 2014 - last edited December 2014
(This isn't a huge deal but would like to get it to work if possible.)
I went ahead and got Mass Effect 1 and 2 via Origin and it works ok but the DLC does not seem to be registering to the game. (I originally had it from Steam but I didn't have the DLC for 1 and 2 so I took advantage of the sale )
C:\Games\Mass Effect\DLC\ contains stuff, in DLC_UNC and DLC_Vegas folders.
The configuration tool (MassEffectConfig.exe) lists both DLCs and their product keys.
I've set MassEffect.exe to Windows XP SP2 Compatibility mode and to run as Administrator (as recommended by some other posts) but, no dice.
Windows 7 x64 Ultimate
AMD Phenom II X6 1090T Processor
8GB RAM
NVIDIA GeForce GTX 580
December 2014
I have it working.
I did a full reinstall but to be honest I think the problem was I still had my profile from my Steam install and this time I renamed the Documents\BioWare\Mass Effect folder to "_Mass Effect" and just copied my Saves over to the new folder.