Windows Essentials is good as a firewall, (just select that portion), but for Antivirus I swear by Avast Free.
Get the lastest from Softronic
http://avast.en.softonic.com/ (they pre scan all their site items for viruses). When you install Avast, go for Essentials (which is what they call the free version) and the only thing you have to remember is look out for and untick Google browser and Ask bar option if you don't want them. (It's easy, but scroll down each page during the installation so you see it).
Personally, I still use firefox as my browser, not only am I used to it, but Firefox have a number of useful utilities and safety addons like 'No Script' and 'QuikJava' (which allows you to swtich Java, Flash, Silverlight etc on an off via your desktop). Firefox also has a plug in for Avast. As long as you use a browser guide like Web of Trust, you should have no trouble.
For on demand malware scanning (you should always run more than one periodically) - you have a number of choices including MSE, I'd recommend SuperAntispyware as one of them, as it comprehensive and quite fast.
I'd also highly recommend you look at two other free standalone l programmes called SpywareBlaster and Winpatrol. NB: You do not have to buy the paid 'Plus' versions. I have included the page for the free version download. I have not tried WinPrivacy yet, but I am considering it.
More info here:
SpywareBlaster:
https://www.brightfort.com/spywareblaster.htmlWinpatrol main information:
https://www.winpatrol.com/Winpatrol Free Version Link:
https://www.winpatrol.com/mydownloads/Finally, I am not in anyway connected to any of these software developers, just passing on my experiences.. Hope this helps someone!
gene-genie