MacBook Pro freeze when copying from USB

I have a one year old MacBook Pro running snow leopard.

I was trying to transfer some files from my old WinXP PC to my MacBook using a USB thumb drive. I transferred a few batches of files OK. Then while trying to transfer another batch the Mac completely froze.

The progress bar stopped moving, and the 'beachball' icon stopped spinning. The keyboard and mouse stopped responding too. The power button wouldn't reboot the system.

I had to remove the battery to power down the system.

Restarting the system, it froze on the gray screen.
Restarting a second time, it froze on a partial desktop.
Restarting a third time, it finally booted all of the way.

Question: Is my system now littered with 'garbage files'?

If so, what do I do to get rid of them?

Can I do anything to ensure the OS files aren't corrupted?

Instead of worrying about "garbage files" you should try to resolve the "freeze" problem first. Run the Apple Hardware Test on your MBP before doing anything else. See this Apple KB article to learn how.

The "freezing" could be hardware related but it could have also been caused by software. However, freezing is usually caused by hard drive or graphic processor problems.

If your computer is still under warranty or Apple care, you might think about making an appointment with the genius bar and have them check your MBP out.

Regards.

appropriate disc?

I went to that page. It says "insert the appropriate disc into the optical disc drive, then restart."

Do I put in my original OS disk, or the SnowLeapord upgrade disc?