I have a backup of that wallet from about 1.5 weeks ago on another machine. Also I have not opened the wallet on the infected machine.
My Question is, What do I need to do after reloading bitcoin core? Just import the backup wallet?
Install core, run it for a few minutes, close it, put wallet.dat and boostrap.dat [1] (optional) in the proper folder, let it sync all the way.
Thanks in advance.
If you created any new addresses in the time after the last backup you might consider doing another backup. Bitcoin pregenerated 100 addresses when you first made that wallet. Those might have been used allready.
[1] https://bitcointalksearch.org/topic/ann-bitcoin-blockchain-data-torrent-145386