Do you have an old, slow laptop which is too slow to run Windows 7 or even Windows XP? Try to install Linux on it, especially the new Fedora 15. I have my HP 500, powered by Intel Pentium M processor series with 1 GB RAM. I install Fedora 15 on it and so far its perfectly working. The Gnome 3 is activated nicely. The installation process had no problems at all. It simply works. :)
The modern Linux also consume more power and needs better hardware to enable all the 3D effects and other features. But don't worry to try install Linux on your old laptop. My suggestion is to try Fedora 15. Its nice and beautiful Linux distribution....