Sorry for the necromancy, but this thread is a top Google result for playing the sims 2 without installing the games, if you already have the files in your harddrive, the reason I'm replying is so that people searching in Google on how to do this can benefit (Google is full of "no, it can't be done" or "impossible, just reinstall" results), which means creating a new topic wouldn't make sense.
Anyway, all you have to do is create the same registry entries of the game that the install disks would have created if you installed normally, these registry entries point to the folders where you have the files, and to other registry entries that tricks the game into thinking you've installed it.
These are 6 registry entries per expansion and have been compiled by
Jeremy at MSFN (click the link and copy the parts that you need.)
What you do is finding the parts that you need to add to the registry (those that have the names of the expansions or stuff packs in them), create a .reg file with the data, run it, and change a key so the game sees it, then the game will run normally.
As an example, suppose I already have TS2 and the NightLife expansion installed, and want to "install" University. I search my 6 needed entries in the above link, copy them to Notepad, and change the relevant parts, those are: since I'm using Windows XP 64bit, I added a \Wow6432Node\ "folder" after every \SOFTWARE\ entry, then I changed the referenced paths to point to the folder where I have the files (D:\Games\Sims2U\), and added a line at the top that made it a valid registry file, it ends looking like this:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall\{8fd3f4ba-a4a6-4380-00a6-cc6853ab2dc2}]
"DisplayIcon"="D:\\Games\\Sims2U\\Sims2EP1.ico"
"UninstallString"="D:\\Games\\Sims2U\\EAUninstall.exe"
"LogFile"="D:\\Games\\Sims2U\\filelist.txt"
"FriendlyName"="The Sims 2 University"
"DisplayName"="The Sims 2 University"
[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\app paths\sims2ep1.exe\]
"Game Registry"="SOFTWARE\\Wow6432Node\\EA GAMES\\The Sims 2 University"
"Restart"=dword:00000000
"Installed"=dword:00000001
@="D:\\Games\\Sims2U\\TSBin\\Sims2EP1.exe"
"Path"="D:\\Games\\Sims2U"
[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Electronic Arts\EA Games\The Sims 2 university\ergc\]
@="QL22Q9764X8JQMHX22PB"
[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Electronic Arts\EA Games\The Sims 2 university\]
[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\EA Games\The Sims 2 university\1.0\]
"Language"=dword:00000001
"DisplayName"="The Sims 2 University"
"LanguageName"="English US"
[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\EA Games\The Sims 2 university\]
"DisplayName"="The Sims 2 University"
"Installed From"="F:\\"
"Registration"="SOFTWARE\\Wow6432Node\\Electronic Arts\\EA GAMES\\The Sims 2 University\\ergc"
"CacheSize"="983398400"
"SwapSize"="0"
"Language"="English US"
"Locale"="en_us"
"CD Drive"="F:\\"
"Product GUID"="{8FD3F4BA-A4A6-4380-00A6-CC6853AB2DC2}"
"Region"="14917"
"Patch URL"="http://thesims2.ea.com/update/"
"Suppression Exe"=""After running a .reg file with that data and adding it to the registry, the game thinks it is installed, but doesn't see it. For this, you need to edit a last registry entry that tells the game which expansions you have installed, it's in HKEY_LOCAL_MACHINE\SOFTWARE\EA Games\The Sims 2\ (or ...\SOFTWARE\Wow6432Node\...) called "EPsInstalled", empty if you don't have any, and has ",Sims2EP2.exe" if you only have NightLife, there I changed it to "Sims2EP1.exe,Sims2EP2.exe", and voila! I could play the University expansion without having to install it, the process can now be repeated for all the other expansions which will be much faster than having the install disks rewrite all the files you already have.
If this doesn't work, the worst case is that you're creating the registry entries in the wrong place, and will have to install TS2 to find where the "EA GAMES" and "Electronic Arts" entries are created, and create the expansions' entries on there.
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