I recently performed a series of Nessus scans for a client who had acquired a competitor. I can't offer specifics but there was a bit of a shocking revelation for me. Some companies are still not actively patching there computers. There was a computer with no patches for an old Operating System.
Microsoft provides WSUS for free.
Patch your systems.
Patching is a base level activity - it needs to be done. You don't have to have a high end software solution for all of your applications. You can even use the Windows Update website to keep you up to date (or patched with the last patches for the OS)
Be safe out there.