If you had a virus or another attack on your machine, and you believe the integrity of your wallet is compromised, then we recommend the following.
- Download and install Daedalus on a new machine. You can download the Daedalus wallet here: https://daedaluswallet.io/#download
- Write down and store your recovery phrase in a safe and secure location.
- Use your Daedalus wallet recovery phrase from the compromised wallet, to restore your wallet on the new Daedalus on the new machine.
- Discontinue using the old wallet.
It would be best if you did this as soon as possible to reduce the chances of losing your ADA.
See also Tips for Staying Safe Online