I'm running Windows 8 and I can still access services by typing services.msc in the run window on my computer.
It still works on my wife's Windows 7 laptop too.
When you type services in the Start Menu search box, what comes up for services. I show a Services with the gears next to it and a services.exe .. of course you would pick the one with the gears.
You might try putting the entire path in the Run box C:\Windows\System32\services.msc to see what happens.
Interesting: On another Win7 computer it works fine.
So this must be a mis-configuration of that special computer. Maybe it was a side-effect of an "optimization" tool in the past.
When I type "services" in the run command entry field then all files from the "Favorites" dir tree appear like
"WebServices Tutorial" or "Development services",....
Maybe the base directory where run command searches for appropriate commands switched in REGISTRY from
C:\Windows\ resp. C:\Program files
to
C:\Users
Is there an ENVIRONMENT variable in Registry (like MY DOCUMENTS) which represents the root/base node for run command searches?