I blame Bill Gates.
Try "alt"+ "4"
I lost access to my Outlook e-mail the other day, Quote: cannot access default files Outlook.psc. and expecting to lose an arm and a leg at the I.T. repair shop nevertheless I took my laptop in, and the man did just that, i.e. restored my Outlook within 45 secs of walking through the door,( and didn't charge me, having emptied my wallet a few weeks ago over something else ) this after a weekend - these things always happen at 16.59 on a Friday - of Googling, downloading rubbish programmes "guaranteed" to enable one to read Outlook.psc files ( or something like that ) Nothing worked, hence my trip to the shop at 09.01 on Monday.
His rationale being that alt+4 re-starts, i.e re-boots ( I think ) which is not the same as shutting down and re-starting, which I'd done many times over the weekend in a vain attempt.
Don't ask me, but give it a try, nothing lost.