What I would do, if this is an OEM laptop - if you made recovery discs when you got the laptop, use them to restore the laptop back to factory-original specs. Otherwise, if there is a factory-recovery partition on the HDD, and a hotkey to trigger it when booting, use that.
Otherwise, if it is a Windows 8, 8.1, or 10 install, then there is a way to "Reset" or "Refresh" the laptop, to remove all user data (and accounts?), and set it back to original installation state. (I've done that at least once on my Win8.1 tablets.)
Generally, there is an option to wipe the drive clean when you do that, so it wipes the free space to erase any user data.
If a factory-recovery is not available, and you don't have the Win8/8.1/10 reset/refresh option, then the next-best is to uninstall everything (using Revo uninstall like you did), and then after deleting all your user data, emptying the recycle bin, and removing backup System Restore points, then install CCleaner and "Wipe Free Space".
That's about the best you can do.
Of course, if you have original install media and a Windows installation key, you could also always use a DBAN bootable media to wipe the drive, and then do a fresh install of Windows as well. You would end up losing OEM programs like DVD playback software, etc., but it would give you a clean and sanitary install as well.