At last, I've got around to trying the process and here are the steps that work for me.
Fire up the PC. Do not open
MES (
MultiECUScan) yet.
Connect ELM cable to PC and car, turn Ignition ON.
Computer may "find" new hardware, wait until it says "ready to use".
Open Control Panel, then Hardware and Sounds, then Device Manager. (Win7, others may vary slightly)
Expand "Ports (COM & LPT)"
Point at the COM port that is your ELM cable, probably the only one listed as you should have nothing else plugged into a USB socket at this time. Right-click and choose Properties.
Choose Port Settings, and change the Bits per second to 115200, default is usually 9600 which won't work.
Click "Advanced" and check that Latency is 1. Click OK and OK to exit this stage. Close All the Control Panel windows.
Now open
MES.
Press F9 Settings, then Interfaces. See if interface is listed, if not press "Scan for interfaces". It should find yours as connected.
Once it has found your ELM cable, set type to ELM 327 1.3+ and under the Test button, set to 115200. Then test it.
If this does not work, try not to cry in the keyboard.
Charlie, I have a KLM cable, never managed to make it work.