Is anyone else using the computer?

You may have ad/mal-ware. Further information can be found in this article; https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware?cache=no

Run most or all of the listed malware scanners. Each works differently. If one program misses something, another may pick it up.

No one else uses this computer but someone is filling up the internet cashe every time I open firefox I know this from ccleaner , and it not just a little its like 15k and its seem to happen as soon as I open firefox and I try chrome and it does the same thing fills up both cashe from chrome and firefox then and malware software it not finding the issue, I downloaded three different ones to no avail

I called for more help.