I recommend that you start out with some hardware tests. The 2 most likely components in my opinion are RAM and hard drive.
To test RAM, see this guide: RAM - Test with Memtest86+
To test the hard drive, use the DOS version of SeaTools
What do you want from a Live CD? The Windows installation DVD works great, if you need to get into a command prompt. If you don't have one, you can create a system repair disc. See this tutorial: System Repair Disc - Create