I don't know much about the hal modification for Windows 7 64-bit since I haven't tried it yet, but I'm confident if you installed the modified NVIDIA driver right now, SLI would enable.
If you need the driver to load in its unmodified form (WHQL certified), anatolymik's solution is the only way to do it (so far), though.
Are you sure the HAL was actually replaced (and windows didn't recover)? Could you check the modified date and make sure?
HALL modified date is 16 September 2009, 18:49:14.
I can use any kind of driver, modded or not, ATM I'm running 190.62 WHQL W7x64.
I'd also tried the DSDT mod directly in BIOS, the DSDT mod was valid, but I faield to do overall BIOS mod ( MEMINIT and a couple more modules went, misplaced, I blinded trusted in cbrom195 to do it, insted of I manualy correct it), one DFI M3H5 down until I can get an SPI programmer.
With an ASUS Crosshair III/BIOSTAR 790GX A+, I can´t get the DSDT patched in to resgistry, BSOD on reboot
Note: I also had to do a different way on DSDT mod, HEXed the iasl dumped dsdt??.dat, for adding SLI certificate (DSDT size and checksum must be corrected) and then asl /loadtable for patching registry. For verifying DSDT table, I use RW/ACPI Table/press "F3" to load table file, if everything is ok we can see DSDT table and SLIC incerted.
To make the binary 8bit sum to zero just mark the entire code in e.g. winhex, calculate its 8bit hash. Then use the odd windows calculator in hex mode, byte.
Enter the calculated hash (byte) and operate logical 'NOT' plus one.
Modify a zero byte (at the end of code) with the result and recalculate again the hash of the binary, the result should be zero then.
