Which version of Hoster are you using ?
Also which version of Windows are you running ?
Did you upgrade or install any other programs just before this happened ?
How did you delete the songs, was it through the edit dialog ?
Can you play any songs at all ?
First from your Build songs database dialog, are all the folders listed in the bottom left Payne showing correct ?
If your songs are on an external hard drive does the volume letter match the file paths showing in the file paths list ?
It is quite possible that when you connected an external drive that windows changed it's drive letter, if this is the case you can reset it by following these instructions
http://www.mtu.com/kb/kb/index.php?a...&id=4&relid=10
When you say "my small monitor shows only half if I fit the show by stretching and resize it manually"
Are you referring to the computer main dialog or the small preview screen in the main dialog or the extended monitor?
One thing you can try first for this, from the Tools Menu/options press the reset displays button.