Using a creative sound card. . . . .

I have been upgrading drivers and removing syem tray apps to try to get the game to be more stable under XP.

Steam might have issues with Skype and Afterburner so I don't play with these loaded amymore.

Upgraded catalyst drivers to latest (non beta) 13.1 for XP for my MSI 7850 card. Upgraded G19 keyboard driver. Upgraded Edimax driver and RAlink utility to the version in the so-called Windows 8 Beta file. Disable windows indexing before play. Put Norton internet security suite into "silent" mode before play. Unloaded RAlink.

These are all good things for me to do before playing ANY game and improvements seen not just limited to LH.

BUT

It SEEMED to me purely subjectively that I got a huge improvement in stability, smoothness of play, and reduction in frequency of system lockups when I used creative's driver updater utility to go to the latest version of the sound drivers. Creative don't upgrade often and I was on the immediately  previous version which was years old.

Also

I can exit the prograam go off and do something else in XP and re-enter the program three or four times without issue. The issue I was having where the program didn't completely shut down then on subsequent reloads went haywire seems to be better now.

Hope this is of interest to someone.