If your Pc was infected the hacker probably knows your password. He can see your PM's too seeing as he has access to your account.
None of that is any good. If this is the only proof you have that is the reason why theymos won't answer you.
If your PC is hacked it is very difficult to get your account back, it has happened a few times where theymos was tricked into giving an account to a hacker by accident and people got scammed so in these kind of cases he only gives over the account when there is no doubt whatsoever who the owner is. Because you were infected with a torjan the hacker knows almost everything about your account, even a signed message would not suffice in that situation. If I was you I'd make a new account and start over, but it couldn't hurt to occasionally remind theymos about the old one just in case.