To reply to your question its for system resources I don;t know your
total hard drive size or if its a SSD hard drive cause they figure up
different than PATA drive, but back to your question windows required
at least 20% of your total hard drive size for system resources IE
Swap file, virtual memory, Master File Table so on.
What this does is allow the operating system to use that free space
for like virtual memory, swap file, when your doing a medium to heavy
work load your ram can't handle all the work load that is needed so
the hard drive is use for virtual memory storage so the ram can be
free up for other stuff need by the operating system.
Open up defraggler and look at the main screen click analyze button
look at the pie chart and see the used space versus free space. if the
free space is less than 1/4 of the the pie your cutting into system
resource you need to either clean up unwanted files, remove useless
program if its a factory built computer or if you can do the stuff
then get you a bigger hard drive or external hard drive, and last
procedure.you can do windows compression to free up space.
If your pie chart looks good and you have more than 20 percent free
space try increasing your virtual memory in your system properties.
Dave