my ps2 will not play ps2 games

[arthurx1234]

Can someone give me some advice?
my ps2 which is NOT chipped and has not had the back off-ever, will not play original ps2 games anymore.
dvds and cds play ok but when i insert a game the start up screen starts and then the drive just clicks.
what is the problem?
can i fix it myself?
any idea how much it will cost to repair?
any advice/help will be gratefully received
cheers
arthur