System Drive (C) losing disk space on its own

[booster22]

PC specs:-
CPU - AMD FX-6300 3.5GHz
MB - ASUS M5A78L-M/USB3.
Memory - Kingston HyperX fury DDR3 4GB 1866 RAM x2 (total 8 GB).
ATI Radeon 3000 HD onboard VGA.
OS - Windows 7 Ultimate 64 bit Service Pack 1.
Windows have not been updated for sometime now.

I've both "Malwarebytes Antimalware" and "K7 Ultimate Security" installed.

PROBLEM - My cabinet cooling fan has been making a lot of noise and vibrations of the cabinet for past 1-2 months, and I fixed it by changing it only yesterday i.e. February 3, 2018.

But, On January 27, 2018, after running for a few hours, my PC started acting abruptly.
In those few hours I just watched youtube videos continuously. After that I played a movie using VLC media player, it was lagging and stuttering in between, which I thought could be due to a bad print. Midway between the movie, I received a message saying that Application needs to shut down due to lack of space on system drive (C), free up some space on C, then restart the application.
On checking, I found that my C drive had only 2 GB space left, against a usual of 20 GB for a 107 GB partition. Nonetheless, I transferred a few desktop items to other partitions (E), freeing up space and then finished that movie, and a second one without any lag or other messages.

Thereafter, I ran a complete system scan using "Malwarebytes Antimalware" and then using "K7 Ultimate Security". Nothing found. But since then, whenever I start my PC it shows different amount of space available on C drive, sometimes, 20.9, 20.7, 20.6, 20.5, 20.3 etc (all in GBs). Also as system keeps running this available space keeps changing, usually decreasing but a few times it increased as well, luckily the decrease has not bee that drastic since that incident on Jan. 27,2018. t usually decreases upto 19.-- GBs. This never used to happen earlier.

Also, when today I tried running my Windows update, it just did not start. I had to shut the MY Computer>Properties window down using task manager, as it became unresponsive. Twice. Thereafter I got the message that Windows Explorer will restart a it was not responding.

So guys, please tell me what seems to be the problem. Was it the fan messing up with the HDD since they are supposed to be sensitive to motions etc.? Or is it any malware or virus? Or some other issue?

Also please inform me about the steps that I can take to resolve this particular issue, as well as steps to prevent any such further issues.

Any input or resolution is greatly appreciated.

 

[SkyNetRising]

Update your windows. If you haven't done it for a while, it's not so easy anymore.

First install this (windows update service @Computer Management/Services has to be stopped before installation):
https://www.howtogeek.com/255435/ho...l-at-once-with-microsofts-convenience-rollup/
Then this:
http://wu.krelay.de/en/2016-07.htm
After that windows update will start functioning normally and you can install all the rest of updates in usual way.

Download and installation of updates takes a lot of space. But if you have 19GB free, that shouldn't be a problem.

 

[madmatt30]

Hibernation files, ram pagefile, unused system uodates , restore & backup files.

All these can take up huge amounts of disk space & are generally hidden from windows explorer views.

 

[Cyanide2x4]

I used to experience the same problem for a very, very long time and sadly I could not find a simple fix for it either.. But there are a few things you could try;

- Try Windows' built-in 'Disk Cleanup' feature
- Give CCleaner a go (although most of the time this doesn't help at all, it's still worth a go) and if you are more experienced with this sort of tool, I'd recommend 'BleachBit'
- Uninstall programmes that are on your C drive and install them elsewhere
- Go through your %AppData% and if you suspect there are leftovers (files, folders, etc.) from programmes you uninstalled long time ago, then delete those files/folders. Be extremely cautious with this point and if you don't know what you are doing, then just don't do it. If you really do not know how %AppData% works, then just skip this point.
- Run 'chkdsk' (more info can be found e.g. here: https://www.partitionwizard.com/partitionmagic/c-drive-keeps-filling-up.html)

Finally, although far from a perfect solution, you can try a fresh Windows re-install if you have the possibility.