If you were using Windows 7 Beta or RC, then the modification worked but the activation for Windows Beta or RC would not be able to be activated. The SLIC v2.1 only works for the RTM or OEM version of Windows 7 Utimate.
i'm using the latest win7 RTM iso. after a couple of reboots i checked system settings and now it says i have 29 days left to activation. so again it may have not worked. can you please provide the link for the ASUS P5KPL-CM modded bios.