Reinstall the Play Store app using the apk file. Download the apk file on your phone, then open it, then reinstall it. The file is too large to be attached to the thread so here is link: (login with 4shared before downloading it.) ww.***********/mobile/4J9Ojb7rce/comandroidvending-80250010-v45.html?
Solved it with a Google search. Go to Apps, All, scrolled all the way to the bottom and found Download manager had been disabled - somehow. Not by me. Enabled and all is well.