Instructions
Double click the Mass Effect 2 icon on your desktop. Wait for the configuration dialog box to appear.
Click video on the left sidebar.
Select windowed for the first option.
Select the smallest option under resolution. Depending on your monitor and graphics card, this resolution will vary, but the most likely option is 640 x 480.
Turn off any of the remaining options that you can. For example, you can disable high quality bloom, film grain, dynamic shadows, motion blur, light environment shadows and spherical harmonic lighting.
Set the remaining options to the lowest variable possible. The remaining options include the number of cinematic lights and anisotropic filtering.