Long Drive Access Time in WIn XP When A File Is Selected

[TELEMETRY]

i HAVE A 40 GIG DRIVE PARTITION WHICH CONTAINS TWO FOLDERS. One of the folders contains around 20 gigs worth of files, as soon as I select this folder to display the contents in explorer,, the hardrive frantically accesses for around 10 minutes, the files are already displayed but I cannot do anything with them till it stops. Again if I then selct one of these files to open it, the same happens again.
Any help with this one would be very much appreciated, cos I'm lost and fed up with waiting each time. I have defragged the partition in question but this does seem to have helped.:flames:

[bigjackusa]

Does scandisk show any errors? Is this the only partition on the drive? Is the drive on a channel with another drive? Is it set to use DMA?

[TELEMETRY]

The drive in question has two partitions, as far as I can remember it is set to dma. The problem does not occur within the other partition. I will run scandisk to check for any errors to make sure there are none. I wondered if it was due to any security or sharing settings as I have recently been locked out of this partition by some rogue security settings and I may not have set them correctly in re gaining access.
Any further advice can only help

[bigjackusa]

Is it an NTFS partition with file encription?

[BrokenSaint]

Riddle me this "batman" whats on that partition of the drive you are having issues with?
When was the last time you Defragged?