Hit Windows key and R together to get Run box. Type: regedit and hit Enter key. 

You need to explain the problem more details I guess. Otherwise partners cannot understand your issue. 

Hit the PrintScreen button, all your screen will be record as an image. Hold down ALt+PrintScreen, the activate window will be saved.

First of all, you should check if the software company has delivered the new version of 2015. Then you can just go to the official site and find the information you need. There always exist instructions and some other wizards on the sites to teach you how to install or update the antivirus version.

Can you explain your problem in detail? I don't understand what the problem is. I suppose you face with a home page redirect or replace problem? Am I right? If so you can have a look at this page and see if it can help. Or please provide more info. about your problem and I would be happy to look around it and help you. 

To reset a home page on browsers is not difficult. You can have a look at this post as it tells about general methods dealing with home page replacements or redirects. Not specific though.

I advise you say more about the problem. In most cases, if you want to uninstall a software, you can go to control panel and if your icons or options are show in category, you can see Programs(under is there says uninstall a program). Click it and you will see your program list. There list all your programs and you may right click on the one then choose uninstall.

If you are talking about a rogue software which often stays firmly on computers and can also be considered as viruses, you need to do more work. Check this to see if this is what you need.

Toobars are sometimes helpful and sometimes annoying. They can conflict with some other functions of the machine. I searched some for your question via google and there are so many guidance on removing various kinds of toolbars. But they all have one thing in common is the manual removal instruction so I suppose its a popular and useful method. See this and have a try pls. Goodluck,

That is a browser hijacker problem. Trovigo.com is not technically a computer virus, but its activities turn out to be very annoying and malignant, such as making changes to your browser secretly, displaying unwanted or misleading pop-up advertisements, and extremely difficult to get rid of from the browser. I would suggest you uninstall it from your computer manually because I've tried several removal tools but none of them helped.