I checked my log files today and noticed the following entry: 27/2/2012 - startup scan - active boot sector of the 0. physical disk - probably unknown TSR.BOOT virus - unable to clean All scans show up nothing. I have run rkill before scanning and it did not find any malicious programs to terminate to assist with the scan. I don't know if it is relevant but my HiJackThis log is also clean. From the log it appears this was a couple of months ago - I never noticed any warning about the find. All subsequent startup scans have also been clean. Should I still be concerned and if so what should I do next?