I Can't sync iphone 5s because files can't be read

OK, so i've had an Iphone 5S for about 8 months or so, 64BG version. set it up on a desktop computer, sync'd a ton of music over, including purchased itunes music.

previous computer ended up being trashed because of a drive failure, so new desktop, new drives. the first time i try and sync with the new computer, it tells me i can trash everything and start again, so ok.

now when i try and load anything onto it music wise, i get "could not copy -filename here- because the file could not be read". the files are stored on 1 TB partition of a 2TB hard disk, the disk is new, no issues, and all music plays fine in itunes.

the error occurs on random files, if i repeatedly sync, the file it failed on sometimes gets synced, and then another file fails. i've got over 1100 songs to copy, and it manages about a dozen at a time sometimes, and sometimes only 3.

i'm at my wits end now, i've tried renaming the itunes library file, uninstalling itunes and reinstalling, using a different location to store itunes files, downloading the purchased itunes albums again (which fail to sync as well). sometimes it hangs on one song, refusing to get past 50% copying, sometimes it says it's synced when it hasnt. almost all the files i am copying were on the iphone originally, and i've tried trashing the music library and *only* copying the AAC albums i've downloaded from itunes, to no effect.

someone help me before i take a hammer to my iphone and swap to Android.