MS DOS box flashes up - related to dllhost.exe COM Surrogate?

Hoping somebody might be able to help me out. I've been noticing a very quick flash of an MS Dos Command Prompt box every 30 seconds or so. The box isn't visible for long enough to read the title bar or the contents, but every time it happens, the line in the attached image appears in Process Explorer then turns red and disappears as the box flashes up. Can anybody figure out what's going on? I've ran various malware products and anti virus scans but nothing is being found.

Thanks in anticipation of any help.

Managed to right-click and get the properties for the dllhost command in ProcExp. I copied the process id and searched the registry but am none the wiser. See attached screen caps. The process is relating to something called WinInetBrokerServer.

Something UsernameIssues posted a while back:

In ProcessExplorer (to see fast starting stopping processes):

Options > Difference Highlight Duration... = 9 seconds.
View > Update Speed = 0.5 seconds

Try a clean startup though - Troubleshoot Application Conflicts by Performing a Clean Startup