Don't know if you still need the upgrade for the Blackjack, but herre you go just in case:
For downloading WM6.1:
FOR XP:
http://ars.samsung.com/customer/usa/...ROD_SUB_ID=558 &PROD_ID=957&AT_ID=132706
FOR VISTA:
http://ars.samsung.com/customer/usa/...ROD_SUB_ID=558 &PROD_ID=957&AT_ID=132707
Follow the instructions carefully except, leave your SIM card in the phone. For some reason, removing the SM card creates recognition issues. You will have to have the software from the CD that came with your phone in your computer because your phone will have to be linked to the computer for the download.
Turn off any spyware programs and your firewall.
MAKE SURE TO TURN THEM BACK ON ONCE THE UPGRADE IS COMPLETE!!