crashed in the middle of a download? accidentally ctrl-alt-del kazaa? don't want to dload 500mb more of a corrupt file?
if you are using kazaa, morpheus, imesh , and getright simply copy TEMP file to another location, extract it with winrar and record the size extracted [ it will say corrupt tho] then dload 10mb more and do the same, if the new extract is bigger.. the file is not corrupt.
Also you can use this to verify if the file is REAL [ eg. if yiou think the file is doom 3 and the folders are named "unreal xxxx" and "d3d" is in the extract you know its fake ]