Hi Wirbelstrom,
Thank you for considering Sony Community!
Loss of data is one of the possible effects of magnets to your computer, especially if the storage type is a hard disk drive (traditional mechanical hard drive). We recommend not exposing your Vaio nearest to magnetic objects.
For further assistance regarding your concern, please contact the Sony offices/Sony representative offices nearest to your place of residence in Asia Pacific region http://www.sony-asia.com/countryselector.html?hpid=countryselector:AsiaPacific. Due to proximity, they are in a better position to respond to your questions or concerns.
Regards,
Vincent