Read Fixing a Frozen iPod. If you’re fairly familiar with hardware, you really don’t have to read what’s noted on the article; its what noted on the comments: (#4) When the iPod is OFF (very important, hard drive must not be spinning) put the hold switch on and give the ipod a few firm whacks on a covered surface. I’ve been having issues with my 40G 4G iPod skipping songs, not being recognized by the PC, and I was bordering on desperation already on fixing the darned thing. The comments on the article related so many success stories, I just had to try it. AND IT EFFING WORKED.