iPod iPod sync questions

Hello. I was just about to turn on the music syncing when it said something like, "This iPod is synced with another computer. Do you want to erase it and sync with this computer?" I've recently switched computers, so that's probably why it said that.

Now, does that mean it's going to erase absolutely everything on it? I have movies on it that I didn't keep in iTunes for space reasons. But I don't have Movie sync turned on. The only actual sync that's going on is photos and calenders & contacts.

So my question is... if I turn on the music sync... will it erase just the music, or everything?

Is there a way to de-sync it from my iMac? I'm not sure I remember actually turning on the sync feature on anything on the iMac, but if I did it's probably for the photos.

Which program do you recommend? I used one once, but for some reason it seemed kinda flaky... heh.

Well I've set it up to sync after recovering the movies from my iPod, since I deleted them from iTunes to save space.

I didn't know that you couldn't set it to sync music, but still be able to manually manage movies. That totally sucks and makes absolutely no sense.

I want to be able to put movies on my iPod and not keep them in iTunes because they take up so much space altogether.

So I guess I'll have to stick with manual everything then.

Unless there's some way to sync music and still be able to manually manage movies? Other than buying an external HD.