Lost Clusters on HDD
Frequently running Scandisk or chkdsk can help save your data. Hard drives can develop bad clusters over time, and those utilities can help retrieve corrupt data, and also prevent data from ever being written to those bad sectors again. Running these disk management tools will help reduce crashes and further loss of data. They may also help make you aware of impending hard drive failure.
Lost clusters in a lost chain
A typical error, such as "lost cluster in a lost chain" indicates that data is present but there are no pointers pointing to that data. You can run chkdsk to attempt to recover the files, or you can simply repair the errors by selecting N when prompted for action. This will correct the errors but not save the data. Or you can press Y, which will attempt the associate a folder to that data. If a folder cannot be found, it will save the data in a folder labeled .xxx. The "xxx" is a sequential number, so the folder will probably be named .000 if the folder does not exist.
This utility exists in Windows 9.x systems, such as Windows 98 and ME. To access this utility, navigate to START>PROGRAMS>ACCESSORIES>SYSTEM TOOLS, then scandisk. You will be given the option to do a Thorough Scan, which is recommended as it physically scans the surface of the drive for errors. You can also specify if you want the errors corrected automatically, which is normally fine unless you want to attempt to recover the data.
Chkdsk is available in Windows 2000 and Windows XP. To run a chkdsk, go to My Computer and right-click the drive you want to scan, then select Properties. Under the Tools tab, you will see a section for Error Checking. Click Check Now. Again, you will be given options Automatically fix the errors, or to attempt to recover the data. You may be prompted to reboot so this utility can run before Windows loads. This is normal.