updates to iphone 3GS

It's Windows. You need to disable firewalls/av/malware/antiphishing software.

Maybe someone else will have suggestions. I haven't used Windows in a few years.

Try connecting your computer directly into your modem, instead of thru a router. Some routers stop downloading large files and don't restart the download.
Check your power settings and make sure computer is always on, hard drives on, and usb root hubs are not allowed to conserve energy.

First update U iTune desktop app Itune 9+ at less
When you conect your iPhone to computer you have to set up ethenet conection on your phone; it should be local host network when it syn with your iTune .desktop Win.
Use wired conecting and syn.
Check your PC internet conection (security)LAN set up
Check windows security authorisation
Try all first if still not work I show you other ways

Some people just can't get the download from Apple direct, not sure why, always say they have turned off firewalls, connected directly to modems etc,etc, but still unable to download.

If you are still have problems, try here

http://www.ismashphone.com/2010/09/ios41-direct-download-links.html

It needs to be saved in this location on your computer

Mac: ~/Library/iTunes/iPhone Software Updates
Windows XP: C:\Documents and Settingsusername\Application Data\Apple Computer\iTunes\iPhone Software Updates
Windows Vista/7: C:\Usersusername\AppData\Roaming\Apple Computer\iTunes\iPhone Software Updates

Once you save it there, start iTunes and it should find it. Then select Restore and it should proceed.

Note: If there is any other file in this location remove it so only this new file is save there.

Hope this helps