I just got my 4 Gig memory stick but for some reason after I formated it, I could only play one game (only one would show up when i went to Memory Stick under the UMD option) on the memory stick even though I have like 4 on it. After I formated again, I put only 1 game on it and it work, but then if I put a second game on it, it won't show up, but the first game still does. So the problem is not that the games aren't real, but something I don't know about. If anyone can help me that'd be great.

did you buy it off ebay?

dude if its from ebay it may be FAKE!!!!!! does it play PSX though????

A bit more info would be helpful; such as where did you get it from, how much did it cost, and what brand is it?

I got it off of Ebay... But like I can still play Killzone or something on it... just that the next games I put in doesn't show up.
I also tried saving with my Killzone but then the saved file it says is corrupted, Dunno if its my memory stick or if it was just a bad ISO.

sorry bro its probably fake, ebay has been known for that, some people put smaller memory chips in the stick and hack it on the computer to read full capacity even though it isnt there. then you can transfer files to it but after the first file it wont read anything else you put on it. it was big with the 2gig cards people would put 256 chips or watevers in the 2gig cards. try putting videos on it then using your computer to play them directly off the MS. if you cant then its definately a mem stick problem

I'm pretty sure mine is a 512 then... because anything above 512 other than a few doesn't work. The ISO for Monster Hunter Won't boot up but smaller ones do. Killzone was 517 so I guess it boots but probably crashes at the end or something. Can't even save with it.