my drive C:\ problem

hey all,

i use windows 7 ultimate, on acer notebook.

my drive c:\ has 48.7 GB size.

normally, disk used space is only about 18.4 GB. however, sometimes, used space increases to 19.5 to 20.1 GB.
used space increases without installing any software. i tried to clean up disk but there are only few junk files.

i tried to figure out the total files' size on drive c:\
i summed with hidden files. the total file size is only 15.7 GB
the question is where are those 3+ GB size used for? why is used space increasing without installing any software?
how can i find out? can anyone explain me?

thanks in advance...

Hi sailyneseng,

Nothing to worry about here. I believe the three odd gigabytes are occupied by system files necessary for normal performance. I can't think of a reason off the top of my head why your used space would be expending, but I'm sure there's nothing to worry about. I'd recommend running a disk defragmenter to clean everything up. Would you like instructions on how to do this?

Thanks,
Harvey Meale

1) The extra space may be taken up by System Restore points (if you have system restore turned on) located in the "System Volume Information" folder at the root of the drive. You can check and reduce the amount of drive space used by System restore, see here.

Make System Restore Use Less Drive Space in Windows 7 - How-To Geek

2) Another culprit is the hibernation file (if you have hibernation turned on). If you dont use hibernation, you can simply turn it off by typing the following command at the command prompt:

powercfg -h off

3) You can also save some space by deleting the contents of the folder C:\windows\softwaredistribution\Download. Doing so will not uninstall any installed updates.

This will also delete the existing hiberfile.sys (again located at the root of the drive).

Alternatively, you can reduce the disk space occupied by the hibernate file, see here.

How To Reduce Hibernate File Size In Windows 7