If you need an OS CD, you get an OS CD. I know there are web sites on how to create such but the days lost on such mean that its your choice and never mine to do that.

As to shutdowns. Since this is XP, try http://www.diefer.de/speedswitchxp/ and set the speed to as low as it can go. Then scan with Grif's tools at http://forums.cnet.com/5208-6122_102-0.html?forumID=44&threadID=311989&messageID=2880351&tag=forums06;posts#2880351 ejecting all they find with the stock settings.

If it still shuts down, tell us about your yearly cleaning.