Free HDD Space Rapidly Increasing

[helpme3948]

Short story: My HDD space keeps increasing quickly. Is it deleting files? Do I have a virus? I have VERY important stuff on this computer!

Full story:

I have a laptop with a 160 GB HDD (140 something usable I think) and since I was getting low on space and I needed a lot of space to transfer some large files, I uninstalled some programs and deleted some files I didn't need. It started getting full a few weeks ago as I remember. So whenever I get too low, I free up some more space. I finally managed to get about 20 GB free and then I filled up about 10 GB (I needed some files from another computer for what I was working on). So anyway, at one point I checked My Computer to see how much space I had left. Then I checked it again a bit afterwards. It had increased by a number of a couple of GB even though I had just transferred more stuff (besides the 10 GB)! I checked again in a bit and it had 15 more GB free than before!

This is terrifying me. I'm afraid if I do a virus scan, important stuff could be deleted while I wait. I really need to know what to do. I couldn't tell if anything was missing, but I had so many files on it anyway, how would I know unless they were straight from my desktop or documents folder. I had Avast (free version) running, but I know it needed updated. I already have MalwareBytes on the computer, but it's free version so it doesn't do realtime. I have no idea what to do. I'm really hoping it's not a virus. Please help! In the meantime, I turned off the laptop and removed the battery. If you need more information, just ask.

One more thing, I couldn't connect to the internet (can to router though) with my laptop either, but I can with other computers in my house. That could be some sort of network issue (and I have satellite internet so I tend to write off weird internet problems, though the other computers ARE fine).

[Gammo]

Hi,

I don't think this is malware related, but lets take a look to be sure.

You can transfer the program with an USB flash drive.

Download ComboFix from one of these locations:

Link 1

Link 2

* IMPORTANT !!! Save ComboFix.exe to your Desktop

• Disable your AntiVirus and AntiSpyware applications, usually via a right click on the System Tray icon. They may otherwise interfere with our tools. Here is a guide on how to disable them:
  Click me
  If you can't disable them then just continue on.
  
• Double click on ComboFix.exe & follow the prompts.
  
• As part of it's process, ComboFix will check to see if the Microsoft Windows Recovery Console is installed. With malware infections being as they are today, it's strongly recommended to have this pre-installed on your machine before doing any malware removal. It will allow you to boot up into a special recovery/repair mode that will allow us to more easily help you should your computer have a problem after an attempted removal of malware.
  
• Follow the prompts to allow ComboFix to download and install the Microsoft Windows Recovery Console, and when prompted, agree to the End-User License Agreement to install the Microsoft Windows Recovery Console.
  

**Please note: If the Microsoft Windows Recovery Console is already installed, ComboFix will continue it's malware removal procedures.

Once the Microsoft Windows Recovery Console is installed using ComboFix, you should see the following message:

Click on Yes, to continue scanning for malware.

When finished, it shall produce a log for you. Please include the C:\ComboFix.txt log in your next reply.