i found a site on how to do it, you just have to copy the files manually. here it long very long..
i dont doubt theres another way tho but this worked for me
For NT users, Fallout can be installed manually. However, in order for the game to be playable, you must have at least NT 4.0 with Service Pack 3. Just follow the following instructions, and keep in mind that the letter D is being used for the CD-ROM drive in this example. Please replace it with your CD-ROM drive letter when doing this:
1) Create a folder called fallout for the game (example: C:\Program Files\Fallout)
2) Copy D:\program\win\falloutw.__ to the folder you created. Then, rename the copied file to falloutw.exe .
3) Now, depending on the installation size you want, do one of the following:
Small Installation: Do not copy anything else.
Medium Installation: Copy D:\master.dat (318 MB) to your fallout folder.
Big Installation: Copy D:\master.dat (318 MB) and D:\critter.dat (150 MB) to your fallout folder.
Humongous Installation: Copy D:\master.dat (318 MB), D:\critter.dat (150 MB) and the entire d:\data folder to to your fallout folder (example: C:\Program Files\Fallout\data).
4) Create a text file in your file folder (example: C:\Program Files\Fallout) called fallout.cfg and add the following line to it, depending on your installation:
Small Installation:
[system]
master_dat=d:\master.dat
critter_dat=d:\critter.dat
[sound]
music_path2=d:\data\sound\music
free_space=0
Medium Installation:
[system] master_dat=c:\games\fallout\master.dat
critter_dat=d:\critter.dat
[sound]
music_path2=d:\data\sound\music
free_space=0
Big Installation:
[system]
master_dat=c:\games\fallout\master.dat
critter_dat=c:\games\fallout\critter.dat
[sound]
music_path2=d:\data\sound\music
free_space=0
Humongous Installation:
[system]
master_dat=c:\games\fallout\master.dat
critter_dat=c:\games\fallout\critter.dat
[sound]
music_path2=c:\games\fallout\data\sound\music
free_space=0
To play Fallout under Windows XP, make a shortcut to the falloutw.exe file. Then, right click on the shortcut, select 'Properties->Compatbility', and select either Windows 95 or Windows 98. The game should work fine then.
