rescanning is already done, and now the conflicted transaction is removed. but the (n/a) transaction is still there....
I also think virus is possible, but why does the virus smart enough to just issue the transaction right before i send out the funds?
if it issue the transaction right after i send out the fund(may be 1 mins later), i would not have this issue because my fund already sent out.
if it issue the transaction long before i try to send out the fund, i will notice and know it is because of virus. now this timing looks like i got a system issue and suddenly send the funds to someone's wallet...
It is possible for a virus that has sufficient privileges to hijack the network stuff to slightly delay the broadcasting of your transaction do that its transaction is first. It also needs to wait for you to enter the wallet password so that it can decrypt your password to steal all of your coins.
i am using AVG on the computer, and i put it to full scan last night.
it found 2 virus on the computer
1) pooler CPU miner 2.3.1 (minerd.exe)-> Trojan horse Bitcoin (this one we know it is wrong judgement long time ago)
2) guiminer-scrypt (poclbm.exe) -> Trojan horse generic12_c.CCZX
guiminer got infected is not what i expected, so i decided to do a clear installation later and change the password of my wallet.
seems we come up to a conclusion that my system is infected and my funds are stolen.
Giuminer might not have been infected since most mining software causes false positives. However, it is possible that you do have a virus and that guiminer was the virus.