Yesterday I spent the whole day trying to make ubuntu 11.04 32bit version work on my HP 620. I installed it using pen drive alongside windows and here is what happened. I was able to boot it right after installation and when I restart it, or shut down and then start, after selecting ubuntu from grub menu screen went completely blank and nothing appeared even after 10 minutes. I reinstalled by different settings 4-5 times hoping it would work. I was freaked out at this point. But then by chance I figured it out, that problem was with the wifi, which I don't use, so had it turned off from windows. Tried different things and came to conclusion that I had to keep it on or ubuntu wouldn't load. In short this almost solved problem.
But at the same time when I was thinking that it is in fact a good operating system and maybe I'd shift completely by removing my windows, some more problem were discovered. So here is the list of current problems;
1. First of all, bluetooth behaved erratically. Strange behavior it shows and I haven't been able to send a single file from it.
2. A press of wireless key, which toggles wifi and bluetooth, would hang ubuntu. Have to use power button to turn off directly.
3. Not able to shutdown, restart, standby, nothing. Didn't try hibernate and suspend. For standby, screen goes black with all lights still on, and not able to recover from state. And for shutdown and restart, everything vanishes except wallpaper and it's stuck there. Have to use power button to turn off directly in all cases. In short, it's only method to turn off.
Now to smaller problems which I could live with but it's nicer to have bug free system.
4. When booting ubuntu, shows background and afterward shows ubuntu logo for 2-3 seconds and boots instead of showing logo entire times, and sometimes this screen becomes of small size and shifts to upper left corner.
5. Sometimes when I boot, resolution is disturbed and it is in ratio of 3:4, 1024x768 and I have to change it manually to get full screen.
6. While ubuntu is running, wifi indicator light keeps blinking alternating blue and orange lights, which otherwise is blue for on and orange for off. And when it is stuck while shutting down, it stays blue.
This all I experienced in only one day. Then I didn't try to install again or maybe I could have some other problems. Maybe someone could guide me how to make it work
PS: Thought about trying 64bit version but I don't have much capacity left in me to download 700mb more at the speed of 20kb, spend another day with it and still not see it work
edit: Forgot to mention that everything is working fine on my friend's acer aspire mini laptop (don't remember specific model). I myself installed ubuntu on it yesterday.