Reply to the Original poster.
Are you sure the email was legit? That email sounds fishy to me as it is very hard to have a steam account to be hacked. If it was, I would check your P.C. first with a virus checker and then use an ad-aware checker like spybot.
Why would someone hack your steam account? I've been on it for over 7 years now and not once have I had a Hack attack (touch wood). I would also post on steams customer support page asking if the email was sent by them and if it is correct. A google search should also tell you if the email is a scam email. I hope you did not click any of the emails links, by the way?
Regards.
CaptEngland.