installing games?help

[sssh89]

i copy games of androis like asphalt 5 into sd card then then when i try to install it via explorer it says the application cant be installed on this phone
plz heppppppp til now just assasian creed is installed from lot of games i've downloaded from internet

note : my phone is xperia x10i running android 1.6
thnx from now

[Weapondrift]

1) are you sure the files are .apk?
2) settings>applications>unknown sources SHOULD be checked
3) if you are on ATT they have blocked the ability to download programs that are not on the market. Essentially making you ONLY use the market.