I'm sure there are other utilities out there but check out the following Microsoft KB article to calculate SHA-1 hash values for file validations. The alpha-numeric string after clicking the SHA-1 link on FileConnect should match the one you calculate using an SHA-1 hash tool on your downloaded file.
http://support.microsoft.com/kb/889768
However, if your downloads are getting cut off, perhaps you should open up a case with Symantec. Even with an apparently successful d/l, I'd still do an SHA-1 to give you peace of mind that you got the whole file intact.