Computer starts up until it gets to e-machine logo

I would start by unplugging all devices, drives from the PC. Printers, Cameras, iPods. The only thing that should be plugged in is the keyboard, mouse and monitor. If that yields no result, it's time to open the case and disconnect your optical (DVD/CD) drives, hard drives, and floppy if you have one. From there I would try changing RAM from a working machine that has similar RAM (DDR, DDR2)

You could also try resetting the CMOS by pulling the nickel shaped battery out of the motherboard. That should at least get it past the emachine screen and get you some more specific error messages.