WD500 my book ,asks me too clear space to copy,its only 8% used??

Home edition" Keeps saying need to clear disk space ,Its almost empty only 8% used.i now file type matters alot .Can i change file type to ntsc? or does it stay on fat32.Forgot wich type is larger.it works fine now, just wont copy lg files 6 gb like movies & games yano what i bought it for .LOL.Im using XP pro sp3. It use too work fine on previous os install. 1st time owner builder.i built pc in 02/09 for $1250.oo tiger&new egg .it smokes a $ 2000 dell xps .triple the warranty too .

Thanx alot apprec it


Q9400-2.67 @3.4GHZ_ GA-EP45-UD3P_ 4gskill 1066_ 750W Pc power&cooling_XFX 4890_ Lian-Li K7B_ acer 23"H233H_Arctic Cooler7_WD cav 640_WDmb500ext._2 LG super multi drives_Lg blueray_