TD, take a look at Kaspersky Anti-virus, it's readily available at Kaspersky.com. The free product is so ungodly thorough that you'll need to let it run and do nothing with your machine, with your modem shut down. It will find anything on your machine that's nasty or even close to a security risk. A good place to start and most companies, if they feel you may come back on them financially for allowing this sort of fraud to take place, will at the minimum change out your account info
Just make it known that you want to escalate to that person's manager that they haven't done enough to ensure your concerns are being addressed properly.