Download RawTherapee 4.0

Want download the latest version of RawTherapee 4.0. on my Vista Home Premium 32-bit with 1.00 GB.

RawTherapee warning says:

Don't even try RT 32bit below 2GB of memory. To let it run stable during coversions (which use the most RAM):

Set Windows 32bit in 3GB mode. Look here for how to set it, and here is the full explanation. If XP has problems booting, also add /userva=2900 after /3GB.

So, I start as they said with "here for how to set it.....

1. Right-click My Computer and select Properties.
2. Click the Advanced tab.
3. In the Startup and Recovery area, click Settings. The Startup and Recovery dialog box will appear.
4. In the System startup area, click Edit. This will open the Windows boot.ini file in Notepad.

etc.....

Everything went well up to point 4. where I am stuck as I do not have the option Edit...

Anyone to tell me how can I deblock this situation ?
This is a link to Rawtherapee procedure if needed
Ollis RawTherapee Windows Downloads

Thanks very much.

It looks like Raw Therapee is recommended for machines with lots of RAM:

RawTherapee Maximizing memory efficiency

The page has a link to tuning 32 bit Windows machines with 4GB of RAM to maximize the memory's effectiveness. There is no benefit to playing with the settings if you have 1GB of RAM.

Incidentally, you've stumbled into a Windows 7 support forum. There may be more appropriate ones out there for a Vista user.

The instructions you followed are for XP, not for Vista or Windows 7.
Since Vista, Windows uses a new boot manager and new way of storing boot entries to replace the ntldr and boot.ini files in XP.

Enabling 3GB support in 32-bit versions of Vista and 7 is quite easy. Simply open an administrative command prompt and type: bcdedit /set increaseuserva 3072
That's all you need to do. Reboot the system for the setting to take effect.

Also mention that the /3GB switch is useful even with just e.g. 2GB physical RAM, because it moves the barrier for virtual RAM also.