Do not use an unsecure operating system when dealing with money. I hope this experience will be a valuable lesson for the future. Any man can make mistakes, but only an idiot persists in his error.
I use windows on a day to day basis for business. Is a clean linux virtual machine with a firewall as good as a dedicated mac or linux laptop?
For offline wallets, it is generally recommended to create a completely isolated working environment by booting a distribution of you choice from a liveCD. However, a clean virtual machine should suffice for online trading.