Getting Rid of This

I feel really sure that this is definitely the work of a trojan or some other form of spyware, but I've done two full system scans with Malwarebytes and Norton. Neither has been able to identify anything. Would anyone have any ideas?

Uh, what's the problem? Are you opening the temp file or is that just randomly popping up or something?

My bad, it appears every time that I open up my computer.

All I can really tell you is it's a temporary file. I'm not sure what's making it try to open like that. Have you tried deleting the file? What's in your startup directory? Run msconfig and look at the startup tab. Take note of odd entries. M$ has an article that describes your situation slightly, might be worth a try to look at this.

Run regedit and post the items at these locations:
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\RunOnce
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\RunOnce

Startup issues can come from a number of areas so it's hard to give you just one answer.

Better than msconfig and regedit: autoruns. Google it, download it, boot into safe mode, run it, google anything that looks suspicious or save a log from it and post it here if you're lazy. You can turn off any startup programs or services you don't want or think might be malware. If you disable something Windows needs, you can always boot into safe mode and turn it back on.