Make sure you have the Microsoft Visual C++ Redistributable Package installed, it's needed for the new HLA.dll system to work. Use the links depending on your OS, x86 or x64.
Microsoft Visual C + + 2008 SP1 Redistributable Package (x86)
Microsoft Visual C + + 2008 SP1 Redistributable Package (x64)
1: Install 7.62 in a new folder, like C:\games\7.62\. Do not intstall the game in your Program Files or User folder, that will cause problems with vista/win7
2: Extract the Unofficial Patch files to your game directory, including this file:
msvcr71.dll
3: Run the PatchMe.bat in your game folder to pack up the files in an AZP archive
4: Extract all the files from Media.pack_pt_1.rar, Media.pack_pt_2.rar and Media.pack_pt_3.rar to your 7.62\Media.pack\ folder.
5: Extract the Blue Sun Mod Base files to a temporary folder, then copy them to your game directory.
6: Run the BlueSunMod.exe to start the game.
If you have the Russian or German version of the game you need the comaptibility patch for the respective version. those packs includes the right E6.exe and are needed to get the game working.