Okay, here's my plan for putting Windows 7 on a USB drive.

1. I install VMWare on the school computer.

2. I download a Windows 7 installation file.

3. I install Windows 7 on the VM with 25 gigabytes of storage allotted

4. I export the file system onto the host and copy it to my 64 Gigabyte USB drive.

5. I restart the computer and attempt to boot from the USB as if it was a PE.

I expect this to take me multiple periods but since I'm the only one who really uses that computer lab (there's 3-4 more with faster computers) I don't think that'll be a problem