Whenever I download big files, such as movies usually 700mb or larger, I keep having to reset(unplug and plug in) my motorolla surfboard modem.

I can download as many songs as i want, 20 plus or more smaller files (3-4 mb) at once without incident. Just when I download large files.

It goes back to downloading, then around 10 minutes later i have to unplug the modem and plug it back in again.
then modem is 6-7 years old, its from tim warner.

any ideas.

Thanks
Mike