My computer powers on but locks up at the "Starting Windows" screen"

marcus, try to start your Windows in safe mode and see if you can check on your device manager which, if any device is giving you trouble. Either uninstall the device, or try and get the right driver for it. "To get into the Windows Vista and Windows 7 Safe Mode, as the computer is booting press and hold your "F8 Key" which should bring up the "Windows Advanced Options Menu" as shown below. Use your arrow keys to move to "Safe Mode" and press your Enter key.

With some computers if you press and hold a key as the computer is booting you will get a stuck key message. If this occurs, instead of pressing and holding the "F8 key", tap the "F8 key" continuously until you get the startup menu." If none of that works you may have to try a System Restore. Hope this helps, good luck.