Lubuntu 14.04 help?

I have a Compaq Evo with Pentium 4, 781MB RAM, 160GB HDD with lubuntu 13.01 installed. It runs very well on there with no lag or wait time at all. Boot time is 23 seconds. Big difference from when it was Windows 2000 and boot time was 3:06 and it had a 9 second delay. But anyway Ubuntu 14.0 came out yesterday and lubuntu 14.04 came out today. I upgraded my ubuntu laptop to 14.04 no problem. (Dell inspiron 1525). This compaq while it was updating the update manager crashed right in the middle of it. The computer will no longer allow things to be installed, update, or uninstalled. It says ubuntu 13.01 has run into error when you try to do something with it. I tried to do the update over but the reminder would not come up. I did it through terminal and it would run into error. I work with computers with my life and I do know that fixing this would be as simple as uninstalling lubuntu 13.01 and reinstalling lubuntu 14.04. Is there any system restore type thing like windows? I want to try to avoid a system re-install because that would take up alot of time. I only have 3 linux computers and Im slowly getting use to linux. The rest of my 21 computers run windows and the other two run DOS.