Why is Handbrake increasing my file sizes? Almost doubling all videos?

I downloaded Handbrake to reduce file sizes for Minecraft and TF2 videos, but when I try to compress them, the file sizes are increasing. I've found videos with recommended or "the best" presets, but all of the ones I have tried almost double my file sizes, while they work perfectly fine in the videos. Anyone know what's wrong?

I got a sign saying my MacBook air might have 5 viruses?

It showed me a sign saying that my MacBook Air might have (5) viruses and it prompted me to download MacKeeper. My friend downloaded it and her computer slowed down until she removed it completely. Is there a way I can check for viruses without downloading anything?

Added (1). Please answer it's the newest MacBook Air I've only had it 2 weeks and seriously don't want any viruses! I haven't downloaded anything on it by the way except Minecraft and MacKeeper, both of which I deleted as soon as I got them. There are no traces of them on my computer

Added (2). The sign popped up on my homepage, but when I clicked the top of it, it was labeled Safari in the top left corner of the screen.

Added (3). I didn't click the link on the sign, only the grey top part that there's on the top of every MacBook app

Added (4). What about the anti-virus software NetNanny? My Mum's friend downloaded it on her son's MacBook and nothing has happened to it.

Minecraft multiplayer not working? - 1

My minecraft multiplayer isn't working, and yes, I do have my HDMI cord hooked in. Single player is working, but no matter what I have done, multiplayer (offline) won't work. Does anyone know why?

What is your favorite hacked minecraft client?

What is your favorite minecraft hacked client that you love to use?
Also, is there any free clients that will make you invisible AND have all the other cool hacks.
ALSO: can someone direct me to a place where i can make my own hacked client, if possible.

What's wrong with my mouse?

It only happens when I play minecraft. It's almost like it has momentum. For example, I go to look left and it spins out of control and I end up looking at the sky. Or I go to look up and I end up spinning out of control and fall off a cliff. It also is like skipping. When try to turn or make fine movements lke you need to when crafting, the cursor is skippy. Sometimes it's like this all day, sometimes it's only like this for 30 mins or so then it fixes itself, sometimes it's not like this at all. I have no idea what's wrong with it.

Really bad performance issues on a gaming pc?

So I recently got a message saying my computer is low on memory and literally 2 minutes after that popped up all my programs have been crashing. Then when I try to record with Fraps on minecraft it crashes and for me minecraft runs smoothly but right as I hit F9 (which is to record) everything crashes. My PC specs are down below I don't remember the exact name of my motherboard. (FYI I custom built this pc)
AMD A6-7400K
8GB 1866 Ram
MSI motherboard
500watt powersupply
Diablotek case
This is so frustrating I'm trying not to get mad but its really not that easy espcially when you put alot of time and effort into something.
I've had this built for over 2 months now so today it has just done this so its really confusing.

Added (1). i also got a 120gb ssd and 1tb external hdd

How to upgrade a normal desktop pc to a gaming pc? (specs below)?

System model- Acer Aspire XC -605
processor- intel core i3-4130 cpu @ 3.40GHz 2 cores, 4 logical pro…
RAM- 4 gig

basically, i have very limited PC knowledge and would love some help in upgrading my desktop to run games well (I like minecraft modpacks like FTB infinity but it often has some insane framerate drops) any info into what i should be looking for and how much it'd cost would be incredibly helpful.