defragmenting ce.net 4.2

this is a newbie question. is there a way to defragment or do a disk clean up similar to what is used in windows XP ?

What exactly did you want to defragment? The CF card or internal flash disk? The Storage Control Panel applet that comes with Windows CE 4.2 should do the trick. Outside of that built in tool, I'd avoid 3rd party software like StorageTools. There have just been too many complaints about them corrupting data to reccomend them. If you just want to defragment the CF card, use a desktop. You are better off just using a desktop to do it for removable media.