How to recover my unused space in C drive

Question

Total size of my C drive is 265 GB, normally i don't store my data in this drive, just install a lot of applications. The day before yesterday, it had free space of almost 130 - 135 GB which i checked around a week ago, only i use my laptop and no new application is installed after that. The day before yesterday, suddenly windows showed me a warning message something like You are out of memory. Then i checked and found that my C drive is almost full, in fact few MB is remaining! Then i urgently uninstalled some applications, removed temp data etc and gained around 12 GB.

Yesterday i run my laptop very few time, but today i noticed the free space is decreasing in C Drive again and i started to find the reason, then i remembered, two days ago i run an exe file found in internet, but it didn't work as expected, but hanged my PC couple of seconds, then i ignored it. I suspect now, that file left any virus in my pc and the virus is doing something wrong now. I noticed in my C drive, there is a strange named folder something like 3500e567-e89b-12d3-a456-426655440ZZZ...ZZ....Z.ZZZ and inside it, there were many folders with the similar name and inside each sub-folder, there were 351(perhaps) files. And the sub-folders are keep creating!

Then using Batch Command i removed that main folder and then i installed a licensed anti-virus which removed some viruses after the scan. After then i recovered some more spaces by various ways and now i have 22.4 GB free space exactly and no space is decreasing then.

I checked major folder's size in C Drive using Batch Command and the total of the sizes used is around 85 GB. So still C Drive is missing around 150 GB!!!

1. Can anybody please guide me how can i recover this space?
2. Also does anybody have any information about the virus which creates files & folders with the name like GUIDZZZ...ZZ..ZZZ.Z ?

FYI: I have checked the drive for error checking tool in windows with no success.

Answer 1

Well, i have resolved the issue and i got back the unused storage of the C drive. In fact WinDirStat solved my problem, using this tool i got to know which folder was eating my storage.

There was a sql server database log file got increased suddenly to 150+ GB and the used size was not showing in the windows properties dialog while i check the size of the root folder Program Files, it was showing the used size of that folder without the file size of that database log file, don't know why, might be a bug of Windows! Now using WinDirStat i traced that file and i shrinked the database log file with the help of SSMS(sql server management studio) and now i have around 175 GB free space in my C drive :)

So my first issue is resolved. Still i didn't get any information about the second issue, as i have not suffered any more with this issue later, this issue could be ignored.