I have an ASUS Lappy that is 64bit Windows. I accidentally installed the 32 bit and it didnt like that lol.
In my opinion the Lag Fix is not worth it. I have read where it caused a lot of problems for people when they tried to undo it, including me. It soft bricked my phone when I added the "disable_lagfix" file.
If you are using a method of lagfix that is not from Voodoo then I would think twice. The Voodoo lag fix works great but disabling it is not always smooth....lol. The official Voodoo Lagfix for the fascinate is not posted yet on Project Voodoo Project Voodoo
I am not sure how much more simple I can make it hehe. As far as I know there is no one click method. The method in the beginning of this thread is pretty close though and it does still work after the Update.
Just try all the modes for USB Connections until one works even mass storage making sure the SD card is mounted.
Also for reference but i'm sure you have read this already:
1. Check to make sure you installed the Samsung Drivers
2. Make sure your phone is connected using the original cable that came with the phone
3. Verify that debugging is enabled.
4. Try to run it again
5. If you are receiving errors then your phones drivers were not installed
6. If you are having a different please post here so we can help you.
Finally if you need more immediate help then check on irc.freenode.net #samsung-fascinate
Some times you have to just keep trying.