4. Install the Beta version of Skype
This version seems to be a bit better than the current official release from Skype. A number of known bugs and incompatibilities has been fixed in this beta version. Download link pasted below;
(No Available Beta version at the moment, the last beta version has now been released as an official version)
Just to check if they are affecting Skype processes in any way. Just don't browse any webpage or use any application that uses internet while your anti-virus or firewall is turned-off. Immediately reactivate them after checking/testing.
6. Do a "Complete Uninstall", Then reinstall Skype.
Here is how to completely uninstall Skype (just back-up all important files and information that you feel is important to you). This will remove all traces of the Skype application so you can install a "fresh" copy of Skype.
How to Completely Uninstall Skype
7. Run Basic Computer Maintenance
such disk defrag, registry cleaning, disk error checking, etc - and also run a full virus scan (just to make sure that your computer is free from any virus/malware that are possibly affecting Skype performance). You can also delete any unused or unimportant programs or applications in your computer.
8. Reset Internet Explorer to Default
Regardless of the browser you set as default, as Skype uses Internet Explorer engines. You can also delete temp files, browsing history and clear cache. Also disable or remove any unused or bad IE add-ons or plugins.