IPOD ISSUSES on iPhone4 ringtone problem No soundSkips songs

The iPod on my iPhone 4 has become crazy & Im beginning to get very angry over here.
1. If i play a song on my phone the songs just play like samples before jumping to the beginning of the same song, then it repeats this over and over.
It sounds like there are several instanses of the same song at one point.
2. If i try the next song on the list it doesnt start to play from the absolute start. Instead it sounds like it skips the first few seconds and then plays a sample thingy and jumps to the beginning.
HIGHLY FRUSTRATING!!
3. Also my ringtones (not the pre-installed) doesnt play at all, for example in the alarm clock! Somehow this is connected Im sure!
HIGHLY FRUSTRATING!!
iTunes seems to corrupt the files in some way when I reinstall them on the phone. They all play just fine in iTunes btw.
Nothing wrong with the tracks (or the ringtones). Both play just fine on the computer, on iTunes, and about 2 weeks ago just fine on the iPhone too!
The only thing that has changed is that I needed to reinstall WIN7 on my PC and then this @@(#/%) happens.
What to do?
Help appreciated.
(Ive googled this and browsed forums for plain iPods, this has been going on since 2008 at least. Alas I did not find any solution to this specific iTunes/ iPhone/iPod/ringtone problem.)
http://getsatisfaction.com/scifihifi/topics/song_plays_for_a_few_seconds_then_itunes_changes_song
iPhone 4 Windows 7 upgrade 4.2