It's fully OK to remove a USB-stick you haven't written to without properly ejecting it. So that can't be the cause of your issues.
All that rests is to repeat our old saying "You only lose what you didn't backup." So, assuming you don't have a backup, you've got one week to recreate that Powerpoint.
I put my USB memory stick into the Hotel Front desk computer to print a Word .docx file. Their computer initially did not recognize my USB thumb drive, so the guy pulls it out and inserts it into the other hotel computer. Not properly ejected. The second computer reads my thumb drive, but has not Office programs installed, so when I try to click it to open my file to print it, nothing. Computer starts to freeze up. Pulls out my USB thumb drive. Again, not properly ejected.
I get to conference, try to plug USB thumb drive back into my Windows 7 laptop (where I had just been working on my paper) and I get a number of errors.
1. My drive was unreadable and I get a little notification about some sort of drive or corruption error. I clicked on tihs notification but it dissappeared so I don't know exactly what it said. I close the computer and re-open it.
2. Now it reads my thumb drive, and I go into Word to do "Open recent" option and it says it cannot find my file.
3. Repeat steps 1 and 2 a few times, getting mixed results and the error messages that Word cannot find the file or that it is corrupted and Word cannot read it.
4. Run Semantac antivirus scan. It appears to "fix" the problem but I didn't see a report of what it did except it said it was "successful". Now my paper file does not appear at all!!! Gone! And, another file (powerpoint) which I had not even tried to open mysteriously disappears. All the other 100+ files on my drive appear to be fine.
5. I go back to hotel, reinsert my USB into both front desk computers and wait for them to properly eject it both times. My files are not all there, but I can see the temporary files are there when I insert it into these computers.
6. I ran Recuva on my computer and it says that it will recover both files. The Word document pulls up mostly jibberish and then the text of a completely different document (a student's paper that I opened and read like a week ago).
7. Powerpoint says "No text converter installed for this type of file."
HELP!!!!!!!!!!!!!!! I can live without the word document, but this Powerpoint was my presentation for my next conference in a week. ARGH!