The biggest problem with attachments is that they can be disguised as harmless documents or images, but they could actually be an executable file that is going to send a malicious virus into your computer. This could be a keylogger that is going to record all your keystrokes and allow people to see what you type from a remote location. It could also be spyware of any kind and even allow hackers to send or extract files from your computer. For support with your Hotmail email account, please get in touch with Hotmail Help.
Always be careful with addresses that look almost the same as those from people you know well. You might get an email from someone with the same name as someone you know well, but when you check the address, you will notice an extra dot, or perhaps a missing letter in their email address. Just keep an eye out for this kind of things and you should be able to avoid a serious issue caused by an attempt to scam you with emails.