How to store a bit coin on my account? Can anyone tell me how bit coins are stored on my account?

I had a bit coin account long ago and not sure what happened? Can anyone explain in simple words what a bit coin account has? Is it a key ... I am totally confused about it after reading the bitcoin.org website.

My specific question are,


can we have a bit coin account like email account where I can store my transactions.
can I start stop this account wherever I am, say on my pc, on my laptop, on mobile or on an other PC.?
How to identify my account? what is the scope of portability?
Your bitcoins belong to an 'account' that can only be accessed by using a private key, which is in your wallet. You can have copies of that private key/wallet in many places. They all access the same account.

I like to think of it this way... The bitcoin network is like a massive bank full of billions, trillions, and so on of vaults. You can put coins into any vault without needing a key to that vault. You can only take coins out of a vault IF you have a key to that vault (your wallet). Your coins are never stored on your actually computer. Only the KEY to the vault is stored on your computer. That key is used to access your coins. Downloading the blockchain is simply a way of letting your bitcoin client know how many coins you have, who you sent coins to, and who sent coins to you. Its like a virtual copy of those billions of vaults, which mostly all you don't have access to. Only that vault whose key you possess. Good luck!