Defragmenting Hangs at 10%

I’m currently running Windows 98. At one time, I had an evaluation copy of NT4 and partitioned my hard drive. When the evaluation copy expired, I reinstalled Win98 and used Partition Magic to repartition the hard drive back to the way it was originally. Now, when I run Disk Defrag., it hangs at 10%. I’ve tried removing the temp. files, running ScanDisk from MS-Dos with no success. Any suggestions?