Updates fail to download properly

I have been travelling and carrying several computers with me (aboard a sailboat) and am currently in Palau - about 4,000 miles SW of Hawaii. Internet speeds here are very slow and so downloading updates or other items can take a long time.

 

I frequently travel to remote islands and then return after four or five weeks to internet access. When I connect up I typically find 80 or more megabytes of Norton updates waiting to be downloaded. At best this can take a couple of hours, Sometimes, like lately, it can take several hours. Apparently the link can be a bit tenuous and stop altogether while the server does some sort of reset. When this happens, the progress on my update downloads stops (I'm using Norton 2010 Anti-Virus) and the progress box displays that the download failed. When I get it started again, it will sometimes resume where it left off and, more often, it will start over from the beginning. Does Norton not have a system whereby the downloads are saved wherever they are interrupted and then resume again so this isn't all a lost cause? If not, I would suggest that perhaps that sort of service could be provided.  Could this be a problem with both of my Dell laptop computers that run XP Professional, SP3?

 

Yesterday I spent all day at an internet cafe with two computers downloading about 84mb of updates, got to about 20mb left to go when they both stopped downloading. I gave up for the day and came back this morning to discover I now had over 65mb to now download. One of the computers today has stopped and started and put me right back where I started first thing this morning.

 

I would appreciate any suggestions.