You only need one. You can install it in different machines.
Do you mean like: http://linuxcommand.org/
There are HUNDREDS of different distros of Linux. What do you want?
Start here: http://distrowatch.com/dwres.php?resource=major
1) What distro are you using?
2) What is the MODEL of your HP printer
When you get the Purple Screen can you Ctrl+Alt+F1 to get to the Terminal Screen , and try to update from there?
One thought is that you might have a video driver installed. Sometimes when you upgrade to a new kernel you have to re-install the video driver.
It's a bit long winded, but it's worth looking at. Perhaps you should start from the Partition that works and "Solution Two".
When you say it won't reboot, what happens, what do you see?
It may be my imagination but this problem seems to be happening a noticeable bit at the moment e.g. http://forums.debian.net/viewtopic.php?f=5&t=121269
If all else fails you may have to rescue your files and do a new, clean install. http://www.alandmoore.com/blog/2012/02/03/recovering-data-from-a-pc-a-guide-for-not-computer-people/#more-273