just tried then and it didnt work still no sound or sound card being recongnised. What do u mean by /extra folder? i thought you put the dsdt.aml file on the desktop then run ###### and select user dsdt?
Firstly, delete all audio injectors (HDAEnabler.kext, VoodooHDA.kext, AppleHDA.kext, ALC8xx.kext, ALC8xxHDA.kext, etc..). Create a folder in the root of your Partition (where you have installed Lion) called "Extra" (without quotes). Now, insert DSDT.aml in Extra Folder and run You-Know-What and install AppleHDA for ALC887 for DSDT users.