General :: Ubuntu-desktop Package Is Not Installing?

I am using ubuntu for a month. Yesterday i tried to upgrade it from 9.10 to 10.0. Then i had to shut down the pc for electricity failure. After that ubuntu came into halt in boot time and something like recovery shell came. It advised me to use "fsck" and i did that. All were again fine (Except some icon goes from left to right ). Then today i was trying to install "Virtuabox" and it says i need to remove "devicekit-power" package. i did it with synaptic package manager ( with my newbie wisdom , didn't knew it would crample my system ). Then the Empathy gone, shut down button gone ). I then installed some lost package

- gnome power manager
- indicator session
- indicator applet session

but ubuntu-desktop package is not installing. Whenever i try it says to fix broken package and i tried the option in synaptic, but no luck. also tried in recovery mode to fix broken package but it says the same. now i got the empathy and the green sign back ( after installing those 3 package ) but not like it was ( they are now separated , and uglier ). Same problem installing devicekit-power package. it says it is not in repository.

1. Did the 10.0 failure upgrade was behind this thing?

2. Any help installing Virtuabox? it first installs fine ( downloaded deb package ). then it tries to download some extra packages and always fails to download them. tried in command shell as instructed in its website and also treid in ubuntu soft centre but no luck.

3. Is there any way i can install the missing ubuntu-desktop and devicekit thing?

4. Would be very glad if someone tell me about a linux soft that protect my system from my wild exploration and destruction