Parallels 6 on Lion not allowing installation of winxp

I have 17" MB Pro with Mac OS X Lion 10.7.1 (11B26), 4 GB.
After upgrading to Lion, installed Parallels 6. No prob! While installing Wndows XP, getting the error

Your virtual machine may run slow because virtualization support is disabled on your Mac.

For optimal performance, please enable hardware virtualization support in your Mac's firmware.

How to do this, to go to Firmware, I don't know. Any assistance, will be much appreciated.
Read the other threads, but of no use, for specifically this prob. Please help.

 

Please do a search before posting new messages. I found this with thread which has relevant information:

http://forum.parallels.com/showthre...lization+support+is+disabled+on+your+Mac+Lion

Basically it says you need Parallels Desktop 6 build 12094 or higher and that you might need to reinstall it.

 

Build 12094

Dear Joevt,
Yes, I have read the thread, & as I dint find answer to my prob, posted this thread. Let me confirm to you that, yes, the PD6 has the build 12094. I uninstalled it completely, then re-installed it, with the same error. No problem installing PD but when I want to install XP, a legal copy, the same error message shows up.

I will appreciate all your help.
Many thanks.