Ubuntu problem, shuts down and freezes. Help!

[boki_hp]

Alright I'm new in Ubuntu, linux ... I've installed Ubuntu 9.04 and the needed programs made the updates that were in the update manager and the very next day the system shuts down I mean a black screen appears the computer works but ubuntu no, I wait a while and I restart the computer. After that a hour or two i work normally in firefox and then ubuntu freezes i wait about 5 minutes and nothing happens and I restart the computer. The next day once again ubuntu shuts down and after that freezes a few times. And now I'm writing here. It's not my first time to install ubuntu I've installed 8.10 before. I also have win xp installed. Oh and i didn't install the ati driver in ubuntu because in 8.10 I've had several problems with it and I've decided not to install it cause it worked perfectly without it.
If someone knows what is the problem and how to fix ?
Thanks in advance.
p.s. I didn't know where to put this so i put it here, hope you don't mind.

[saikee]

This is Ubuntu's own major downfall if I have to name one. The updates do not always end up with a system better than the one it replaced.

I would re-install the system and say no when invited for the update next time. In some PC the updates work fine but it is not uncommon that some PC may have hardware that cause problems after the updates. We have to give the benefit of doubt that there can be bugs in the updates too, otherwise there will be no point to release different versions periodically the updates can guarantee a healthy system all the time..

[boki_hp]

so you recommend to re-install ubuntu and not make the updates. but I don't believe it's the updates because the updates i made were mostly for the programs. I wanted to ask should I install the ati driver?

[saikee]

How do you know that you might have been updated with drivers not compatible with the installed xorg? When you are supplied with a released version someone has gone through the tests to make sure the xorg would work on his/her PC. The problem can be machine specific with most other users not experiencing your problem at all.

[boki_hp]

ok I'll reinstall the ubuntu. Thanks. I never thought that the updates could be a problem.