Then start with uninstalling the software that you installed. Either, by System Restore, or one software at a time, reboot to check behavior.
Waterfox may not resolve your issue. I was just making a suggestion. Waterfox, runs much faster than Firefox on a 64 bit system.
This is a good Anti-Virus program. http://windows.microsoft.com/en-US/w...ity-essentials
Use Windows Firewall
Adobe Reader is free software that lets you open, view, search, digitally sign, verify, and print PDF files. http://get.adobe.com/reader/
Here's an alternative to LibreOffice. http://download.cnet.com/OpenOffice-...-10263109.html
Hope this helps!