IE8’s Protected MODE can run at low integrity, under which applications can't be launched without the user's permission. Am I right that there’s no point in enabling this, since PC Tools Firewall is already prompting me as to whether I want to allow applications to be launched? Or does IE8’s Protected Mode also offer other protection as well?

Quick answer, use your software firewall (just not the microsoft firewall which is pretty much useless) but keep protected mode if it isn't annoying you for some additional protection.

Protected Mode restricts file writes to low-integrity locations, including cookies. In Internet Explorer 8, medium-integrity applications can access low-integrity cookies without user interaction, by using IEGetProtectedModeCookie and IESetProtectedModeCookie. As always, applications that use cookies downloaded from the Internet should assume that these cookies contain malicious data.

It is a system that basically stops hackers and malware from hijacking the browser.

Disabling Protected Mode may resolve whatever issue you’re having with Internet Explorer, but there is a GOOD chance that it will cause some other issues. The last thing that you want to do is open up your PC for attack from malicious software – so give this matter some serious consideration.
Quote from: BobLewiston on February 28, 2010, 06:40:16 PM

IE8’s Protected Mode can run at low integrity, under which applications can't be launched without the user's permission. Am I right that there’s no point in enabling this, since PC Tools Firewall is already prompting me as to whether I want to allow applications to be launched? Or does IE8’s Protected Mode also offer other protection as well?

Is there some specific reason you need or want to disable it?

Quick answer, use your software firewall (just not the microsoft firewall which is pretty much useless) but keep protected mode if it isn't annoying you for some additional protection.

Protected Mode restricts file writes to low-integrity locations, including cookies. In Internet Explorer 8, medium-integrity applications can access low-integrity cookies without user interaction, by using IEGetProtectedModeCookie and IESetProtectedModeCookie. As always, applications that use cookies downloaded from the Internet should assume that these cookies contain malicious data.

It is a system that basically stops hackers and malware from hijacking the browser.

Disabling Protected Mode may resolve whatever issue you’re having with Internet Explorer, but there is a good chance that it will cause some other issues. The last thing that you want to do is open up your PC for attack from malicious software – so give this matter some serious consideration.

Attention, Allan:

I just don't want to be prompted twice for each application that tries to run, once by IE8 and once by PC Tools Firewall.

I guess I'm a little confused with what we're talking about. What does application launching have to do with IE's protected mode?

IE8’s Protected Mode can run at low integrity, under which applications can't be launched without the user's permission.

Again, I'm confused about what you mean by protected mode preventing applications from being launched without the user's permission. Are you perhaps confusing IE8 protected mode with User Account Control? Or are you talking about remote access?