Ok, in trying to determine where the message is coming from lets assume its something to do with IE which has a 'Developers Tools' add-on facility, so we do a check to see if it is installed or not.
This will require the use of 'REGEDIT' which needs to be used with some care to ensure the registry integrity stays ok.
If ok with this, from the 'Windows Start>search programs and files', in the search window enter REGEDIT, press enter and if Windows requests to run REGEDIT select Yes.
- Click on and expand 'HKEY_CURRENT_USER'
- Click and expand 'Software'
- Click and expand 'Microsoft'
- Click and expand 'Internet Explorer'
Do you see an entry in the expand list named 'IEDevTools' ?
At this stage you can close regedit. If IEDevTools does exist, a later stage will be to try to disable it.