I have macbook pro 2010 i7 with OSX Lion installed on it.
Problem:
My mac suddenly unexpectedly freezes and then nothing, not even option+command+esc helps. So it forces me to restart it.
But now, there comes other problem, because my laptop doesn't want to boot up. It takes it for about 3-5 minutes and often it instead of booting up shows finder folder icon with question mark in it. So I found on google that it means that there is no boot up disk. It was also saying there, that I should reset pram. So I did (pressing command+option+P+R while booting up). My mac started in one minute, what was awesome compare to how long it took before. But it was just for that one time. After few hours it froze again and I had to reset it. It showed the question mark folder again and reseting pram didn't help this time, so I decided to start it with pressed option (don't know how do you call this) and wanted to get to the disk utility. I couldn't. It showed only possibility to connect to wi-fi. I tried to reset it with option button pressed few times, but the recovery harddisk possibility didn't show up. So I got angry and went out with friends. When I came back home, I decided to try again, and the recoveryHD possibility suddenly showed up. So I went to disk utility and found that my HD isn't mounted anywhere. So I mounted it. Then, it still took like 5 minutes, my laptop started up. Since then, two days ago, it happend already 3 times, once it froze right when I booted up. I tried opening my laptop and disconnecting and connecting back my HD, because I thought that it could be just somehow wrongly connected, but even this didn't help to solve the problem.
So, do you have some suggestions what could I do with it?

Btw, I am sorry for my horrible english, but it isn't my first language.