With antiquated components flooding the surplus-parts market and free operating systems only a click away, building a fully functional computer has never been such a bargain. No, the $72 PC won´t replace your new dual-core, Vista-shredding laptop. But with its compact size and solid-state components (no hard drive or CD drive), it´s perfect for building into custom enclosures and for specific tasks like Web surfing or playing games. The computer boots from a USB flash drive running an operating system called Damn Small Linux that can handle just about any job.