Upon starting up my PC some suspisious program asked from internet access, after googling it i realised its malware and I wanted to scan it with Avira but the av was gone. In programs and features in control panel, i could still find Avira and Avira anti virus, which were both semi-deleted, opening avira antivirus just removed it from the list and Avira asked me if i want to uninstall or reinstall. I reinstalled it now and have scanned my OS, removing some more malware along the way. Now my question is how the hell did my av delete itself since i am the only one using this PC, plus from where is this malware coming from, because i have not been downloading anything on my PC, except from sites like Steam, MS store and so on.
Some viruses can delete AV. Always use main AV combined with secondary AV for better security.
The malware most likely damaged your Antivirus program. This is quite common behavior.
Regarding your question where the malware comes from: We need more information, e.g., the scan logs of Avira that show the files and detection names of the malware.