A drive being accessed constantly

I upgraded a Dell computer from Windows 98 to Windows 2000 Service Pack 3. After the installation everytime I do anything on this computer it hits the a drive first. I installed Office 2000. When accessing this program it hits the a drive. It does it for anything you want to do. I am not real familiar with Windows 2000 and do not know exactly where to look to release this. I checked the BIOS it looked fine. I thought about the registry but do not know what to look for.
Any help would be appreciated.