Steam problem - gets stuck on Update

Hey all, when I launch Steam, it wants to update with a message saying "Updating Steam platform", and then shortly later it gives me "Steam is temporarily unavailable, try again later" and then I sigh.

I've tried the obvious, restarting and repairing (in the installer) Steam, but it seems to be not much help.
I've got no ideas of what else I could try, so if you could throw out some suggestions, thanks

If nobody has anything that works, I might try the Steam forums. But once again, thanks a lot if you could help.

There's no use waiting, as the update window just disappears about 10 seconds. The whole Steam does quit (as I didn't see it in the Task Manager's processes)

I find this really weird, as my brother's updated just fine.

If a moderator could lock this thread, that would be great. I got my answer from Steam Support (by deleting all of the Steam files apart from the executable and Steamapps folder then restarting), and now my Steam works fine again