Clearing USB Device

I have this 4gb USB memory that I need to empty with WinXP. The problem is, the files either say: 'Cannot delete: The filename, directory name, or volume label syntax is incorrect' or it 'cannot find source file or disk.' These files are taking up atleast 3.6gb of storage. The write protection is on, with no switch to turn on or off. I'm not afriad to lose any data so anyway to get rid of everything would be nice. Thanks

Have you tried deleting, creating and formatting a new partition using disk management?

Start > Run > diskmgmt.msc

hum; how did this happen? Usually there is a small slider on the device.

Check the disk manager for a READ/ONLY setting and reverse it if present.
If that works, then repartition the device and reformat it TWICE.
(some have found a lost capacity after the first format pass. I found
that a second formatting recovered the full device space, at least for me)