than some kid trys to "hack" you

I'm pretty sure you only get that email once someone has already logged in with your account and needs validation for that new login location. That is, someone knows the account name and password and only needs the validation code to access the account. So yeah, looks like someone might know account name and password and is trying to guess the validation code each time. Or maybe something's just wrong with the system.

or maybe he isntalled steam and logged in at some other pc and it is on auto log in on that pc and trys to log in everytime the pc is started

WTF AOL? I think your PC might be broken.

I haven't logged in steam in a while so it is most likely a hack. I'm having it fixed now.

I kinda doubt it would ask for a validation code if it was validated once already... Unless it somehow expired of course, but I haven't seen that happen yet so I doubt it.

Hopefully it works out well, although I suppose we'll know what happens in the morning.

Change password, change email account associated with steam and the email used for steam.

Wait, I'm not done playing your games...

Probably the Russians, I've seen so many threads on Steam in Russian and they've been known to hack Steam accounts and sell them to others for money.