Parallels Desktop not working after upgrade

Please help. I upgraded to Lion, and since then when I try to open Parallels Desktop I get the following message:

The virtual machine performance may be degraded because the hardware virtualization support is disabled on the host computer.

It is recommended to enable the hardware virtualization support in BIOS settings.

Unable to load Parallels driver. Please restart your computer and try again.

Restart also doesn't help.

After googling a lot, I could not find out BIOS settings on Macbook pro. Can someone help me?

Many thanks, in advance.
-Pramod.