Virus or not,it's always a good practice to double check the bitcoin address you're sending coins to.
You can buy off that code from any hack forums,it's sold openly.
Use linux for bitcoin,makes your stuff secure by 80%
Yeah i've once got this shitty virus on my computer almost sending my bitcoin to Unknown adress but now it's already gone in my computer try check it with your Anti Virus/Malware
I think formatting computer would work, because I hate using Antivirus of it cuts a lot of ram, Though I have a 16GB ram But I hate using Antivirus :]
if you have trouble with the antivirus then choose another one. there are lots of them and only some of them are heavy (for whatever reason). for example i remember Norton always being a terrible AV and slowing everything down.
you can choose Eset Smart Security. it is good and it is light as a feather. it also has everything you need (AV, Firewall, anti fishing, anti malware,...) and checking my task manager it is only taking up about 70 MB of my ram!
try one of those rescue disk live CD thingies. you boot up from them and then they scan your PC and clean it