Have just had Linux installed on a PC running through to our TV.

Had been going through and changing the appearance of various things so we could see icons, title font etc clearly from across the room; mainly making the larger but occasionally changing minor aspects.

Somewhere along the lines, I have managed to loose the "minimize/close/maximize" buttons on the top right of the windows and the windows now stick to the top left of the screen. I am unable to double click on the title bar to maximize the window, click on the title bar to drag the window anywhere, or manipulate the window in most ways.

Here's where it's confusing me .... I can go into Applications/Settings/Settings Manager but when I go into "Window Manager", the window opens but does not contain anything; ie. is blank window?! This also happens with the "Windows Managers Tweaks" window but NO others.

Any help would be much appreciated.

I take it you are using xfce? It sounds like your window manager died. Log out of x and then back in again.

When you ask a question its best to include as much information as you think may be useful. For a question like this for instance, you should have at least included the linux distro, its version number, and the desktop environment you are using and its version number.