If you encountering the error "Mass Effect CD Key not found" during installation:


This can be fixed if you know how to use regedit. Normally Steam adds ME1 to your Windows registry upon first run, but for some reason it doesn't always do it.


In regedit go to:

HKEY_LOCAL_MACHINE\Software\Wow6432Node\BioWare

Expand that "folder" (it's not a folder it's a registry key, but it's a folder icon so I'll call it a folder here) and you should see "Mass Effect"
Click that and on the right hand side should be three "strings"

"(Default)" with the data "(value not set)"
"Flavour" with the data "Steam"
"path" with the data being the install location of Mass Effect (default location: C:\Program Files (x86)\Steam\steamapps\common\Mass Effect)

Make sure those are all there and if not add them.

Also go to:

HKEY_LOCAL_MACHINE\Software\Wow6432Node\Electronic Arts\Electronic Arts\

Expand that and you should see "Mass Effect (tm)" and if you expand that you should see "ergc" (if you click that you'll see your serial key on the right hand side).

Just check that your ME1 key is there, and if not add your ME1 key provided by Steam