General Eris not syncing to computer

So I brought my work computer home to transfer some pictures I took on my phone to my external hard drive, but when I plug my phone into the PC all I get is "USB device not recognized." I don't even get the HTC Sync notification in the status bar of my Eris. I used to be able to do it on my old computer before it died on me. Does anyone have any idea what's going on and how I can fix this problem?

Thanks!