BLACK I.C.E. is an extensive mod of HOI3 under development by Panzeroo and many other members of the Hearts Of Iron 3 forum.
Installing BlackICE may seem daunting at first, but provided you follow the directions here, you should have a relatively easy time with it. Step 1: After you have downloaded BlackICE, copy the installer to the same directory that as the hoi3game.exe and hoi3_tfh.exe files in it. Generally speaking, this will be somewhere like: • d:\games\Hearts of Iron 3 • c:\games\steam\steamapps\common\Hearts of Iron 3 Step 2: Install Podcat's LAA (Large Address Aware) version of the HOI3 .exe file with BlackICE. This will solve a great many issues with the game crashing as it will take advantage of the larger amounts of memory that newer computers can use. Podcat's LAA .exe file can be found in the Tech Support thread on the PI forum •Overwrite the original hoi3_tfh.exe file with it. Step 3: Run the installer. Do Not Change ANYTHING unless you know what you are doing, just hit next until you see finish. Click on finish.