weird problem with my ps2

[gilmey]

i have a problem with my ps2 i play a game then i change the game to another one i reset my ps2 it goes past the ps2 logo then it gets stuck in a black screen then if i reset again the game works fine it happened to me twice .

and if when finished playing a game i eject the cd and reset and let it loaf the browser and then i put a new cd the game works fine the first time
any ideas why is this it just started happening to me now
i have a v5 ps2 with magic 3.1