I've had a similar problem with Windows XP Pro: since I never found a solution and this is the closest internet post anywhere to the problem, I thought I'd post the work-around that I've discovered...
Random (to me anyway) mp3, .mpg, .rar, .jpg files in multiple directories have suddenly become unable to be viewed, played, renamed or deleted. With mp3 files they had 0 bytes and could not be played, with mpg they had no video dimensions. With jpg they cannot "be previewed" by the windows picture viewer or accessed by ms paint, and none can be renamed or moved (yes, while logged in as administrator).
When I try to move them I get an error message 'access denied, make sure the directory is not full or write-protected'. Now being full or write protected is a message is applies to a TARGET directory, but in this case it's the source that is problematic - (Can I comment on the typical uselessness of windows error messages that no-one at microsoft knows the meaning of?)
Now, I recently noticed (don't know if this happened to other files that I had to fix) that while the specific files are not read only, the directory containing these messed up files will show mixed contents with read only files attributes, and when I try to change them the contents and sub-folders I get access denied.
I took a look at the MS 308421 article but that didn't work for me. The only solution I've found so far is to rip them forcefully off the drive and then copy them back (rename, get the write protect error, trigger the Unlocker Assistant, force move to a usb drive, then just copy it back) - voila! everything is fine, 100% success with a couple hundred files (if only Unlocker could do batch commands!). My mp3 files suddenly have size and can be played, renamed, etc. My pictures and .rar files can be accessed, viewed, etc. While Unlocker doesn't find a "locking handle", it can take control of the file with brute force, which suggests to me that some process has locked the file from being accessed, even by explorer (hence attributes skewed), but why random files in random directories?
Anyway, if you run in to this problem and don't happen to have the files already saved somewhere else (go microsoft tech support!), the method I've been using may help you reset whatever the problem is in XP.