[quote1188359652=SpetzNaz]
That means you were VAC banned. Which means that the Valve Anti Cheat system detected an activated cheat while your brother (or you, or whoever on your account) was playing.
Those bans are not issued lightly, and are almost NEVER wrong. In fact, VAC is typically a crappy system because its so easy to slip past it. If the account is VAC banned, there is little to no doubt he was cheating, regardless of what he says. VAC is automated... it detected something. It would have had nothing to do with his score, or anyone spectating him.
You will have no re-course in this matter. Buy the games again, and delete (or tell your brother to delete) the crap from the machine.
[/quote1188359652]
Quoted for truth. A valve employee isn't just going to be like "zomg this guy is good he must be hacking BAN". They don't do that, you've been banned by the (crappy) anti-cheat system. Whether you personally know it or not, there was almost certainly cheating involved. Yell at your brother and have him delete the hacks he found or delete them yourself if you know where they are or if it was you who downloaded them.
Bad luck, but from now on you should either A: Not cheat. or B: Not let your brother play if he's going to cheat.
Hope you're not short on cash.