Upgrade to 6.24 won't find any updates
Following the information on my Drupal install I have tried to upgrade 6.24.
I followed the steps in the upgrade text, removing the sites folder and any special modules used by my site, delete all folders and drop in the 6.24 folders and files.
I run the update.php file but it runs without finding any upgrades. I wen through the sites folder as I had heard that some surviving 6.22 components could get in the way. Inside sites/all/modules/updates there is a complete install folder for 6.22, I'm not sure why. It must do something because when I deleted it I got the white screen of death. Dropping in 6.24 to that same location did nothing.
Any help on how to get past this would be much appreciated. I can't just go for a 6.24 install either until I know why the 6.22 folder is in there and why deleting it causes everything to crash.
Thanks