Can't delete restore point folders

My Mom's Sony Vaio had a bunch of restore point folders (73 of them) dating
way back to when she got the machine. They are all obsolete.

Things are running well, except the system seems a litle slow (it's 1.2
GHz) with lots of disk activity, so I wanted to delete all of the restore
points, defrag the disk once, and re-enable system restore (or system
recovery, or whatever it's called in Vista).

Turning off system recovery did NOT erase any of the RP* folders underneath
the _restore{GUID} folder, nor the data in those folders. There are
severral gigabytes of data there.

Using the Disk Cleanup Wizard to delete all but the last restore point did
NOT erase any of the 73 RP* folders underneath the _restore{GUID} folder,
nor the data in those folders.

I see on a Web site that Sharon F, MVP Windows XP Shell, says:

"Using Cleanup to delete all but the most current restore point, moves
the older relative data up to the newest restore point."

However, it's just not working for me.

After I turned off System Recovery, I tried to manually delete the RP*
folders -- boy, those buggers are hard to get rid of in Vista. I finally
got rid of many of the files and subfolders inside the RP* folders in safe
mode by using DEL with various switches like /S, /F, /A:hs, etc. But I
still can't get rid of the RP* folders themselves!

When I try to delete an RP* folder from Windows Explorer, nothing happens
-- no error message, nothing -- the folder just doesn't delete. The event
log doesn't show any errors either.

**Is there something magical about trying to delete the RP* folders?**

Thanks.

David Walker