When I first put my PC together I would keep an eye on temperatures and fan speeds. It would give an alarm sometimes and I was worried my CPU would fry. Then one day I formatted and never reinstalled the monitering software...and there hasnt been a single alarm since :P sometimes, ignorance is bliss.
Also, in your LFS folder, there is a cfg file. You can change the window value from 0 (not windowed) to 1 (windowed). Of course its much easier to just press shift+f4...
I didnt see anything about this so I thought I would post my own experience on the subject. I did see on the LFS site that the minimum is 1ghz cpu, 128mb ram, and a 3D video card. My main computer is running windows xp, has an Athlon 2000+ cpu, 512mb ram, and a Gforce fx5200 128mb video card. This setup seems like more than is needed as I have never experienced the slightest hiccup, FPS range from low 40's to low 60's. When I go into task manager, I see LFS using 0-20% cpu and 130mb of ram so, I decided to try LFS on a much slower computer. The other computer is also running windows xp, it has a P3 800mhz cpu, 256mb pc100 ram, and an ATi Rage 128 16mb video card. In short, I would say this is the bare minimum computer requirements. In my opinion, the game is still playable, FPS range from 8.5-14. I know most would think the FPS are too low to play but, there is no question that if the P3 machine were all I had, I would still be playing LFS til the wee hours of the morning. Next, I will install windows 98 and try running LFS. If the FPS can get over 20, I would be pretty satisfied.
One question, does anyone know if it is more PC demanding to play or host?
EDIT: Okay, so I installed windows 98, but I also added a couple of upgrades to the slower computer. I swapped the ATi Rage 128 16mb video card for an ASUS V7700Deluxe 32mb video card. I also added a 256mb stick of ram for a total of 512mb. I apologize for adding two more variables if anyone is using this for a reference. The FPS now ranges from 14-20. This still may not sound great but, LFS looks pretty nice, and is more than what I would call "playable". I hope this helps another po' boy like me out there to figure out realistic computer requirements.