[Yukonhijack]

It took me the whole night to find a solution, so this should definitely be added to the OP:

By the way, you must use an RC6 receiver! This is not yet mentioned in this thread.

Problem:
The backlight of your Plasma or LCD interferes with your IR receiver.
If your TV backlight disturbs your IR receiver you will encounter the following problems:

• key presses are not detected
  
• key presses are detected one, two or many many many times
  
• the reception LED of your receiver (if present on your model) is always on or flickering all the time
  

Hint: The best way to test the remote is by using a text editor to visualize the input from your remote.

Solution:
Luckily the solution is very simple.
I wrapped the whole receiver in aluminum foil. (not pretty but effective)
Then I made a tiny hole in it and made it step wise bigger until the receiver receipted again the signal of my remote.
(May be testing other receivers is a solution too, but more expensive.)
Now it works really flawlessly. Every key press is recognized immediately.

Hope this will help some of you.

---

Original Post

Step 4 - Optimizing Remote speed

Devices >> Media Center PC >> Settings >> Adjust the Delays (speed settings)
0/1000/500

Devices >> Media Center PC >> troubleshooting >> My Media Center PC is responding too slowly
0

Devices >> Media Center PC >> troubleshooting >> My Media Center PC responds to some commands either too many times or only occasionally.
0

For me these values work:

Devices >> Media Center PC >> Settings >> Adjust the Delays (speed settings)
0/100/500 (100 and 500 are the default values)

Devices >> Media Center PC >> troubleshooting >> My Media Center PC is responding too slowly
100 (this is the same setting as the 100 above, it is not possible to have different values here and there)

Devices >> Media Center PC >> troubleshooting >> My Media Center PC responds to some commands either too many times or only occasionally.
0 (0 is definitely the right choice)

I have the same problem as you described. Key presses that are not detected and sometimes they are detected one time and sometimes they are executed twice.
I also see the led on my HP receiver flickers and sometimes stays on longer periods. I have got a Panasonic Plasma.

After some testing it seems the original HP remote also has the problem, but not as often as the Harmony.

Haven't been able to fix this for now, whatever I try, even when wrapping it in aluminium foil.
You mention 'Devices >> Media Center PC >> Settings >> Adjust the Delays (speed settings)' and tell 3 values. But in my Harmony software (Harmony 555) there are 4 values:
a. Power on delay
b. Inter-key delay
c. Input delay
d. Inter device delay

What are your settings for all these 4 values?

I really hope I can fix this problem, because it's not fun now to use my remote.

I would like to know this too. What are the delays supposed to be? I also have four settings, but there are only three discussed in the OP. Anyone have any insight?