I installed Win7 RC1 on my main PC with a Dell SLIC in the BIOS (for Vista). The keys I entered were not accepted, it said they are not for this windows SKU. Once I continued without key, Win7 informed me that I may be the victim of software fraud. As soon as I flashed back a "clean" BIOS without SLIC, Win7 accepted my beta key and activated without an issue. So apparently there already is some sort of check for the SLIC, and it doesn't pass.