Posted 11 May 2010 - 02:06 PM
Boot sector viruses these days are so rare that I would doubt that is the issue. As MrBruce already stated, if you didn't do a complete reformat, then it is possible that an infection remain behind. Again, not very likely because even with a quick format, a reinstall wipes out important tables that programs need in order to run.
What behavior are you seeing that makes you think you are infected?