Memory stick not recognised by my pc, but all other pc's?

Hello, i bought a 512 memory stick and i used it for a week, put random files on. Then my pc said that one of my usb devices has malfunctioned, it then fixed that itself... everything else works but my Usb pen... i took it back but it worked there and on my friends PC the light doesnt even flash on the top

Make of USB memory Drive- integral 512 Mb

My PC specs- Amd duron 1.2 ghz
512mb ram
40gb hard drive
Windows Xp Home

Thanks in advance