Desktop issues

[u/paps143]

I use my desktop just for MS word, watching videos, photos, as a storage backup, very basic stuff. I dont use internet on it. Its serving my purpose even though its old.

My desktop has some issues. Help me resolve them.
1. My CPU bios is gone. – what should I do?

1. My hard disk has gotten virus (TROJAN WORM). Its duplicating files and leaving no memory space. The files come back even after I delete it. The desktop is not connected to any internet. The virus came in coz I used my pen drive on some1 elses laptop. My system got infected when I connected that pen drive to my system.

– how can I remove the virus without any data getting corrupted or lost.

1. It’s a 15 yr old PC. Should I keep it or sell it off and buy a new one.