NT fragments pretty fast. You need a defragger. Check through these:

• Executive Software's Diskeeper
• Golden Bow's Vopt
• Norton/Symantec's Speed Disk
• Raxco's PerfectDisk 2000
• SysInternal's Defrag Commander
• SysInternal's Contig
  single-file defragmenter that attempts to make files contiguous on disk. Its perfect for quickly optimizing files that are continuously becoming fragmented
• SysInternal's PageDefrag
  see how fragmented your paging files and Registry hives are, and to defragment them

Want to take control of your PC?

Its the 11th Edition. Need I say more.