Having issues re-indexing HDD

I am working with a clients system (10.6.8, Mac Pro) where I need to re-index his HDD.

About 70 GB's is being used on the HDD, but when I start the re-indexing process, it is saying it will take 85 hours to complete, and so far its been running for two days now.

I've already made sure the system has the latest updates and have ran disk and permissions repair and made sure there were no issues. Also time-machine has never been turned on.

Does anyone know of a possible reason why its taking so long to complete the re-indexing process? Is there anyone to possibly speed it up?

Thank You