clear your browser’s cache and temporary internet files to make sure that they are not causing the issue.
This is often caused by a corrupted file in the browser.

*For Internet Explorer browser: Press CTRL+SHIFT+DEL simultaneously and click Delete
*For Google Chrome: Press CTRL+SHIFT+DEL simultaneously and click Clear Browsing Data
*For Firefox: Press CTRL+SHIFT+DEL simultaneously and click Clear Now

How to Clear Browser’s Cache
http://www.wikihow.com/Clear-Your-Browser%27s-Cache
http://windowslivehelp.com/solution.aspx?solutionid=3c7c3338-369e-4220-b29d-71ce660fe5a0

We recommend that you scan computer for viruses and malware using a reliable Antivirus product.
http://www.malwarebytes.org/lp/malware_lp_form/

I suggest connect using HTTPS.
To do that, follow the steps below:
1. Go to https://account.live.com
2. Under Other options click on Connect with HTTPS
3. Choose Use HTTPS automatically
4. Click on Save