I have a gateway Pentium III 450 running Win98 with 10 GB HD

The installation of a faulty Mcafee signature update file caused fatal errors on my machine resulting in improper shutdowns. The subsequent automatic running of a thorough scandisk continued to give me 550,000 bytes of bad sectors until I stopped automatic fixing.
I have now installed a non bugged signature update file from Mcafee which has solved the fatal error problems. Running scan disk does not give any more bad sectors.

Are the sectors marked as bad actually bad sectors?

If not can they be easily regained as useful Hard Drive space?

Any suggestions much appreciated.