As noted for this to work, you NEED to restore iOS using any mac. I have not had any success with PCs. Use iReb on whichever platform however. download iOS 4.1 ONLY and for the 3GS. apple is ONLY signing iOS for the 3GS ONLY http://iosindex.com/iphone/3gs/4.1-8B117 then connect iphone. Go to iPhone settings in itunes. Hold down option while you click restore iPhone then a file selector should come up. please select where you downloaded file and commence. It is normal to get error 1015 and the iPhone should say to connect to a computer with iTunes. Download iReb next.
http://ih8sn0w.com/
open up iReb and click on the Recovery Mode tab and click "Set Auto Boot True" should then boot into iTunes. This is no guarantee but it worked for me. Any questions, please let me know. I repeat, this may work for Windows but it is MUCH BETTER with a MAC
Exchange Gmail (push email (INSTANT)) https://support.google.com/a/users/answer/138740?hl=en
iCloud-like syncing for Calendar & Contacts http://forums.macrumors.com/archive/index.php/t-1176780.html
Disable Spotlight Search & increase BATTERY LIFE & SPEEEED:
http://www.gilsmethod.com/how-to-disable-spotlight-search-on-the-iphone-and-improve-battery-life
