migrate old pc files to iMac via usb drive

Do you mean Windows XP? That is not called Expedia. It's just XP. Short for "Experience".

https://en.wikipedia.org/wiki/Windows_XP

Or do you mean Windows Vista perhaps?

If so, as said, just copy the files from the PC onto the USB stick through Windows Explorer like normal. Make sure it's formatted as FAT32 or exFat.

Then just plug the USB drive into the Mac Click the Finder icon  in the Dock to open a Finder window and copy the files from the USB drive to the Mac.

click here ➜ Connect and use other storage devices with Mac - Apple Support

Expedia is a website for buying plane tickets, not an operating system to my knowledge? Can you clarify what you mean by "running Expedia"?

With that said, you should be able to simply drag and drop files to a usb drive connected to the Expedia PC and then once that is done, connect it to the Mac and drag the files onto the Mac though finder.

What exactly is the issue?

Your Auto Spelling Correction system seems to mix up Expedia MS Windows XP

It was released to manufacturing on August 24, 2001, and later to retail on October 25, 2001. 

For the full history of MS Operating Systems from oldest to newest

https://en.wikipedia.org/wiki/Microsoft_Windows_version_history

WS-2423 wrote:

You are correct, it is XP. However auto spell is not the problem, I am.

No worries. Glad we got that sorted out.

Happy Computing!.