no i tried hex driver but it didn't work.
the screws has shape just like hex but also have small round thingy in middle of it. that's why hex driver will not fix in there. i would need a hollow hex driver or something.
OH! OK that's better.... you explained your problem now.
That's a security screw. It requires a special screw driver the has a matching hole in the end. Try the DIY store. Most stock them.
The other alternative is to very carefully remove that centre pip using a dremel type tool and very small bit. You can then use an ordinary hex driver on them..
I really don't know why they put those damned things in them. They know people need to get them apart. Once you get them out, I'd change them for ordinary screws if I were you.
Best Regards,
Julian (Fozzy The Bear)