For 32 bits version of Windows Vista, 7 or 8, please make sure to follow these steps:
1) Open a command prompt with administrator privileges
- Open the Start menu
- Type cmd in the search field
- Right click on the command prompt icon and select "Run as administrator"
2) Type bcdedit /set IncreaseUserVa 3072
3) After pressing enter, it should say something like "Operation completed successfully".
4) Reboot your computer.
5) Try running Outlast again
Windows XP 32 bits is unfortunately unsupported, as indicated in the System Requirements. Many players still report running the game just fine however on this OS after following the steps detailed here: http://dwf.blogs.com/......vista.html (search for "windows xp 3gb switch" for more information).