Backup

[fmarcof]

I've a SCPH-30004 with a Messiah 2 on.

When I tried to load the game I got:
a- the initial screen (browser, config), but it's freezed
b- the game runs, PLAYSTATION 2 logo displayed but, after a while returns me to the browsing screen (with the memory card and the ps2 game); if I try to reload it just selecting from this screen I get this error again and again
c- sometimes (rarely) the ps2 not even recognize the disc and says to insert a ps2 formatted media.

I've never cleaned the lens, and I don't know how to do it