Does anyone have any idea what is going on with Steam?

I was playing Skyrim merrily yesterday until about 8.30pm BST. Went off to have some supper and see to my Mum.
At the same time as I tried to fire up Skyrim an hour later I had a Steam client update forced on me, since when Skyrim has not worked.

I verifed the cache - still no go.
Deleted local files...and have been trying to reacquire them all night, only for Steam to tell me their servers are too busy to handle the request.
Tried deleting all but Steam.exe and the Steamapps folder, rebooting the PC and then refreshing the Steam files. Still nothing.

This is all going on - or not going on - on my desktop PC, which is a totally capable beast. All my mods are on there.

The irony is that when I try and download on my gaming laptop, it will start!
And I am having no trouble for example with FONV on the desktop.

Could anyone shed any light? Is Steam having some big issue?
Thanks in advance!