Without free bytes

[XPTO]

Good morning.
The C: disk of my PC has 464 GB and is occupied with about 200 GB.
But I can't use the free bytes! It shows 0 bytes free of 464 GB.

Why this? Is it a virus? What must I do?

Thank you.

[Subtitles]

Assuming you are using Windows O/S
Open Disk Management (in search look for): Create and Format hard disk partitions
It will show you the status of your hard disk.
You might need to create a partition and call it D:\ if it shows an unknown part.
Please be very careful how to use it as you might unintentionally format your hard disk.
Watch few YouTube videos to make you feel comfortable how to use it.

[pandy]

I would do two things:
firstly check your disk for errors (and repair them if they exist),
secondly clean disk space (Disk Cleanup) - there can be junk files (temporary, deleted etc) so they are filling space completely.