How fast does it go to 100%? It could be that it is still defragmenting a aprt of the hard drive. Could be that when it reaches 100% that a applicaiton requests something from teh hard drive and the defrag starts all over again.
well i went to sleep it was at like 5% i come back like 7 hours later its at 53%, the odd thing is from 53% - 100% that only took an extra hour maybe less...