I'm not sure how much RAM LW uses, but if it's running slow it could be a factor of many things such as Internet Security applications, Norton & McAfee are known to be memory hoggers, and alot of games as well, that's if you don't have a graphics card.

If your computer is running 256 MB with Windows XP I would suggest upgrading the RAM to either 512MB or higher, the highest you can get 1,024 MB 2000 SD RAM, 2,048 MB 4000 DDR and 2,048 MB 8000 DDR2 for personal home computers.

Another option could be to increase the virtual memory.

Right Click "My Computer"
Left Click "Properties"
Left Click "Advanced" tab
Left Click "Settings" underneath Performance
Click on "Advanced" tab
Click on "Change"
and make it greater than number suggested.