help!! emails

[Giggsie]

My hotmail email account has been sending out emails to all my contacts. It is an advertising thing www.happyhu.com but I did not send emails but looks like I did how can I stop this any help out there?
this is what emails says
Hello ,friend,
how are you those days ?
i will tell you a good news ,i bought a notebook from this site ,it is orignal ,very cheap price ,fast shipping ,you can check it www.happyhu.com ,they also sell tvs ,mobilephones ,cameras ,gps and so on
thanks
best regards
this is second time it has happened first time it was about an iphone now a notebook why is it possible to do this?

[AlBags]

Firstly, see if you can log in.
If you can, change the password! Something stronger than the old one : )

[ChuckFickens]

change your password, somebody has either figured it out or has been given it, normally by people registering for fake "services" that require you to enter your login details.

https://account.live.com/ResetPasswordDL.aspx

[Giggsie]

thanks have changed password. Thought it impossible to figure out password but some clever people out there. obvious it is advertising the company. thanks for your help.

[squarebear]

You will have been tricked into filling out a form like this:

http://www.square-bear.co.uk/mitsuku/msn.htm

promising new icons or see who blocks you etc.

Once, you fill it in, the scammer then knows your login and password and can do anything they wish.

[Giggsie]

thanks for that squarebear but never seen anything or remember filling out any form and nobody else has access to my computer.