Your Kindle seems to be very unstable. Could be indexing/ downloading gone wrong or the unlightened cover. (You say you have 2,4 GB storage out of 4 GB, so that means you have about 5/600 books on the Kindle (?). Did you load them all at once?)
First things first: get your Kindle fully recharged; don't mind the battery-indicator. Then reboot once or twice.
Faulty cover?: get it out the cover at once and if that solves your problem; phone Amazon to get a refund.
Indexing/downloadproblems?
Check if all your books are indexed (by random search and delete all the ones that are not). If you can't delete the not-indexed books on your Kindle; do it through Calibre (that is, if you're using that). Otherwise you might try it through USB in the documentsfolder of the Kindle.
Downloadproblems: check wether a book is stuck downloading from archives to home or from Amazon to Kindle by----home-menu-view downloading items. That last one should be greyed out = all items downloaded. If it is not greyed out, click on it to see which one is causing the problems and delete them.
Also synch. with Amazon and check it your time etc. is properly set (sounds weird, but sometimes this makes a difference as well).
I hope this will solve your problems. If not; phone Amazon, they've got a good customerservice. They will phone you in Europe if you email them to say it'll cost you too much. Good luck
