Flash Drive Anomaly

I have a 8GB flash drive that has worked fine, but now is not working
right. It is formatted FAT32. It was loaded with a large avi clip.
This morning when I plugged it into my XP machine, the drive was not
recognized (by windows explorer). I tried four different USB slots,
same bad result.
However, when I plugged it into another XP machine, it was recognized,
and worked fine. Same good result a W7 laptop.
I reformatted the thing on my laptop, but it still is not recognized
by the first XP machine.
What should I look for as the problem here? Should I toss the flash
drive?
XieXie
Wei

I solved it.

Wei