Mega 2560 won't upload now?

Hi everyone, I've been working on a project with the mega 2560 board and everything has been going great...until an hour ago. I sat down to continue working on my project and now none of my previously working code works correctly after uploading (nothing happens). I'm on Windows 7 64bit and using the latest arduino software (1.0) and now nothing seems to be working. I went through some of the trouble shooting and still nothing (reinstalled driver, disabled other devices, closed other background programs). I've been checking my code via the serial monitor and before I could get data back, but not anymore. I'm not sure what is going on since I haven't changed anything. I tried the loopback test and that was fine. I held the shift button down while uploading this time and got this message: avrdude: usbdev_open(): did not find any USB device "usb" Can someone help me figure out how to get this working again?

Thanks, -Tyler

Alright, never mind. I got some of it working again, but I can't seem to get the GLCD to work was working just fine. Time to rewire it I guess