I tried formating my USB flash drive as always (it's a 4g Konval thing) on standard settings. When it got to about 75% the computer restartet and now it's 0 bytes and RAW.
I can no longer format it in windows, what do I do?

Btw it's windows vista.

Tried format from the command promt and it startet now it's stuck at 68% checked.

What do I do?

You could try the HP USB format tool.

here: http://files.extremeoverclocking.com/file.php?f=197

It should also work in Vista.

Well I tried format on a windows XP machine that worked in less than 10 sec Weird why it blocked in vista.