Hakutulokset

Reset your keyboard controls to default and the problem should disappear.
Somebody probably bound UP_ARROW to +backwards. You can check it in the console before you reset.

I skimmed through to the important bits an I don't think this Toby is a gamer... or knowlegable of multi-boot systems or partitions... or that installing individual games to a different drive is an upcoming feature of steam itself. Oh and from Both OSes, install steam itself onto the shared drive. Thats probably the easiest way.
Perhaps he has been trained only to handle single OS default install issues. If he's paid, how do I get that job? Sounds nice. (Except I'm a programmer, destined never to speak to customers)

Well if you can't go up to his supervisor and he can't ask the guy next to him what the heck your talking about then he must be the ONLY guy working support tickets(of the 300+ people who work at Valve). Certainly he shouldn't have any problem asking anyone else there to help on your issue.

I think I'll be reading the rest of your messages with this Toby chap, they amuse me.

This might be more appropriate in the VAC discussion forum...

Well, my understanding is VAC detects if you've installed an actual program to alter your gameplay (which is why I avoid most game mods unless I know they're safe). If you're using sv_cheats and all the fun that comes with that there is no problem.
However...
Individual admins on their own gameservers can still ban people from their own systems but can't hand out VAC bans.
If in doubt, don't install any cheats. Nobody outside Valve would know exactly what ticks off the VAC system. I have even heard it doesn't like punkbuster.. the previous anti-cheat system.

By the way, this sandbox mode sounds wonderful. An idea on that is anybody NOT running in sandbox mode can't join and that games should be clearly marked. Also should be a way to turn off all your cheats for normal play. Until then, don't cheat.

People can edit their post so maybe look towards the last few pages, but it could be anywhere.

Well if they ever find a way to legitmately confirm both belong to you, then they gotta write an actual program to merge them. That is probably not gonna happen, not for a while and for now... not ever. Unfortunately.
Now you shouldn't go around selling steam accounts(that is against their Terms of Service), but mabye trade what you can and give the other one to a friend. Make sure they change the password and contact info so if THEY mess up Valve doesn't come back to you. I haven't done this and never will. Really though the other account should be killed off. Too bad games can't be moved over.
Or maybe keep them both until Valve makes an appropriate merge tool. Oh and they probably already know you're the same owner (same machine, IP address, computer name, etc) so why they can't act on it is a mystery.
Good luck and may Valve someday merge your accounts.
But the only way to specifically ask them is to make a support ticket. Raw emails will most likely not be responded to.

Should we tell him about the console commands? press [~] and type help, then press enter. The world is yours. I think one of those resets flags like.. is a door open, etc. mainly for skipping quests and random acts of flying.

Are you leaning on the corner of the mousepad? Maybe your right-arrow key is stuck.
Maybe someone pranked you and put in a turn-right script in your config.conf file...
Before you go digging though, check to see if you get the same from your other games (Portal or Trine, etc). If it does it there too, then its your keyboard/leaning on thetrackpad area/someone using another wireless keyboard they secretly synced to your mac. The usual pranks...
If none of that is the case then L4D2 is misconfigured. Just outright reset all keyboard bindings and see if it still happens.
As for the xbox360 controller you probably have to "reset" the analog sticks. Otherwise center/neutral is turn right and holding left is "don't turn".

Good luck.

You got my hopes up. I thought you found a mod.

If you're switching then only the first time it sees the new OS it would ask.
If you try switching again it shouldn't ask.
Or only run it on Windows7? Switch as often as you like but only launch steam from Win7 (or 8, your choice).