OK for GCS and Nimrod:
1) What OS are you using?
2) Did you uninstall? If not start there! (see my post on that)
3) Give a COMPLETE step by step discription of what you are doing.
BTW lets try to get the MW4 plus IS and CLAN packs installed and working for multiplayer then go from there to get BK installed.
My gut feeling is that the process is not being followed e.g. correct patches....
If you play on the ZONE you can find me there usally around 9pm PST or later look for KaoS_TANKORR1 I am not hard to find.
@ B00l eYe - thanks for all the work bro! (keep it up)
FYI I have MW4 + IS & Clan pack working (all store bought versions on a win98 SE machine) those that use burned version might have issues do to some obscure file corruption or other unknown issue I suggest you buy them if needed
They can be had cheap these days!