How To Use Roboform In FireFox While Stopping It In Internet Explorer for Vista
If you need to use Roboform and your browser of choice is Firefox, but you also use Internet Explorer but don’t want Roboform when you use it, then this is what you have to do:
The process assumes that Firefox is your default browser and it already has the RoboForm add-on installed.
Note: The versions of the browsers used for the following example were Firefox 3.5 and Internet Explorer running in Vista. This process should also work for Windows XP.
[1] Disable Roboform Add-on in Internet Explorer
In Internet Explorer (IE8) go to Tools > Manage Add-Ons

In the window that pops up scroll down on the right to the section labeled SIBER SYSTEMS, where you will see two entries for Roboform and both will be shown as enabled.
Now you want to disable both of these two entries and if you disable one then the other will also be automatically disabled.
Select the first entry by clicking on it.
Click on the DISABLE button.

And click on DISABLE again in this second pop-up above when it appears.
The two Roboform entries will then be disabled and this Status will be seen in the entry display:

You might think that this would be all you would have to do to stop Roboform working with Internet Explorer, but unfortunately this is not the case…
Because Roboform is automatically started when you switch on your computer it will still appear when you use Internet Explorer.
Therefore you have to change the Startup procedure for your computer to stop Roboform starting up.
Don’t worry this does not affect how Roboform works with Firefox at all and is just necessary to ensure it does not pop up when you are using IE.
[2] Remove Roboform from Computer Startup Procedure
Click on the Vista START icon in the bottom left corner of your screen.
Then Type the word MSCONFIG into the search box and when the search completes just click on the MSCONFIG program that appears in the search results above it.
Click on the STARTUP tab in the System Configuration window that appears:

Scroll down until you see the Roboform entry and then…
Click on the check box next to Roboform to uncheck it and then click OK.
You will then be asked to RESTART your Computer so do this by clicking on the Restart button:

When your computer system restarts you will be prompted with the following message:

Just check the “Don’t show this message…” checkbox and click OK.
Then next time you restart (and subsequently) you will not see this message again.
Done !
And that is it – now Roboform should only be working with Firefox and you shouldn’t see it at all in Internet Explorer
Disclaimer
Please proceed at your own risk – this process has not been thoroughly tested, but it did work for me (so far!) – no responsibility accepted for anything that you do, including to your computer!