For some time I used the same solution as the previous poster, i.e. running LCore.exe as administrator.
I don't really enjoy having to remember to run the software manually, or, as usually happens, entering game, finding that nothing works, and remembering that I have to run the software.
I have found two solutions that work.
Solution 1) Open C:\Program Files\Logitech Gaming Software\ (or wherever this is on your computer), right click LCore.exe, select 'Properties', go to the 'Compatibility' tab, and check the box for 'Run this program as administrator'.
Whenever you log in, you will be prompted by UAC to allow the program to run, but at least you won't forget to run it. 
Solution 2) (The solution I use) This solution is a bit more involved, but it does exactly what I want it to. I'm not going to be as specific, because if you don't know how to do the things I'm describing, it might not be the best solution for you anyway. It involves removing a key from the registry and adding a task in the task scheduler.
a- Using 'regedit.exe', find HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\Curr
b- Using the task scheduler, create a task that runs LCore.exe at login (of any user, or, if you prefer, only the user you need this software for, as is my case). Make sure when you create the task that on the 'General' tab you set the task to be run using a user account that has administrator priveleges, and that you check the box 'Run with highest privileges'. You probably also want to add the following as an argument when the task runs LCore.exe: "/minimized".
With this solution, you will never have to think about LCore.exe again. It will successfully run when you log in.
Well, hehe, of course, this has been my experience on the two computers where I have run into this problem. I can't swear that you all really have the same problem. If you do, this will fix it.
