Slow Access to Windows 2003 Server

Before my Windows 2000 Server crashed with bad hard disk. The access time to a folder with many files was several seconds from Windows XP Pro workstation.
I installed new Windows 2003 Server in first partition and restores all program and data into 2nd partttion of the new hard disk. Now the access to same folder with many files is 3 to 5 minutes depend on the various workstation.
Why so slow?????