It's very unlikely that its a virus, despite comments above.

The vast majority of software malfunctions are caused by hardware faults (RAM etc.), misconfiguration, driver incompatibilities, incorrect access rights, shared files being overwritten and so on.

Many of these issues can be complex and hard to understand. It's much easier to just say 'it's a virus', but the chances are it's not.

Viruses actually tend not to cause any problems. It is in their interest to go unnoticed, not to attract attention to themselves by causing problems from which they don't benefit.

Free stuff @ https://poser.cobrablade.net/