Hi - I've got some malware on my computer and i'm considering reformatting the drive. Would i just log in to my account to be able to download Pro again?
No logging in to your account won't download Pro again, you will have to do that, install it, enter the license and then link it to your avast account.
So as suggested give the malware removal specialists a shot at it.
What is the problem, e.g. what malware name, file name and location ?
What program detects the malware ?