Reboot required after installing FW4

I'm using INNO. I've used it for many years. I'm making a setup which will include FW4 Client Profile. Total size of the package including the FW for 32 and 64bit is <50meg so that's great.

On XP SP3 it installs no problem. (No reboot required)

On Windows 7 Pro it installs but the FW prompts for a reboot.

I accept that a reboot shouldn't be avoided but I'd like to install the FW using the /norestart switch. This would allow my installer to install the FW and then finish what it's doing and then tell the user to ReBoot at the end.

I 'could' just prompt for a reboot anyway but my question is - is there any way to detect whether a reboot is required ? After all, it seems that a reboot is not always required ?

Thanks