scan disk/available memory Defrag/not enough free memory

every time I try to do a scan disk I get the message......computer does not have enough available memory how can i fix this also when I try to defrag my harddrive I get the message that there is not enough free memory and I get an id# of DEFRAG009 what does this mean and how canI fix it|?

 

The error is caused by the cluster size of your drive being invalid in relation to it's size. This can occur if you use a ghostlike program to copy a smaller drive to a larger one.
Options are to recreate the partition, or use a program like Partition Magic to adjust the cluster size.

http://support.microsoft.com/default.aspx?scid=KB;en-us;q229154

http://support.wdc.com/tips/index.asp?tip=41