Is formatting enough to get rid of all traces of virus?

I think I have a virus on my computer. Is formatting enough to get rid of all traces of it or is there some way to make sure all data is completely erased from the drive?

Formatting alone is not enough. You should back up all data you need saved then use a data destruction program (Active@ KillDisk is one) to overwrite all sectors on the disk. Then re-install the OS and copy your data back to the drive.