Why would a Steam account get suspended?
If you believe an account has been stolen or hijacked by another user, please review the Reclaiming a Hijacked Steam Account topic.
A suspended Steam account does not mean the account has been VAC banned. For more information about the VAC system, please view this article.
Check the contact e-mail address for your Steam account to see if Steam Support has contacted you regarding the reason your account was suspended - accounts may be temporarily suspended pending verification of purchase information or account ownership.
Steam Support does not automatically contact the owners of suspended accounts in most circumstances.
There is a Zero-Tolerance policy for any violations of the Steam Subscriber Agreement and Online Code of Conduct. All accounts in a user's possession for any of the following activities will be suspended:
This includes using an unauthorized ("hacked") Steam client to access Steam, attempting to register fake CD Keys or attempting to register a CD Key which has been published on the internet.
Any fraudulent credit card use, credit card chargebacks, or Paypal chargebacks (regardless of when the transaction occurred).
Never accept a gift from an unknown user. Any accounts tied to a redeemed gift from a fraudulent source may be suspended.
Do not use Steam accounts which you did not create.
This includes contacting other users outside of Steam or over the Friends network under a misleading screen name or e-mail address (i.e. "Steam Admin", "VAC Administrator", "You Won Free Game Gift") and requesting password or account information.
Accounts which have been bought, sold or traded will be suspended.