Okay, first of all bookmark me, because in the process you may lose me. You can use the bookmark to get back to me. Do this only in case you are using the same problematic computer to talk to me.
Click Ctrl + D to bookmark this page.
Later when you want to come back:
Open the browser >
Click on favorites >
Click on the earlier bookmarked link. You may need to log in again.
Once bookmarked, do this:
Open Internet Explorer > Click on Tools > Click Internet Options > Click on Advanced Tab > Click on Reset > Click on Reset again > Restart Internet Explorer.
Now try to open Yahoo Finance using Internet Explorer.
If that does not work then download and install Firefox browser from this link: http://firefox.com/
After installing Firefox, try opening Yahoo Finance using Firefox.
Let me know if that works.