My unbuntu has been running fine for last 2 years. I've been updating it constantly and it hasn't given me any problems at all, except now.
Everytime I boot my system, the boot now takes longer than it used to before and then when the login screen is supposed to appear it makes the ubuntu drums sound but I don't get the dialog box where I get to choose the user and enter password.
If I press the power switch it gives me Shut Down, Restart, Suspend, Hibernate options. My mouse is fully active.
In the last session when it was working fine, I tried installing a program called pbrt. I hand edited certain pbrt files in /usr/local/ by giving me permissions to write using su. In the same session, gedit started giving me Segmentaion Fault. I opened Synaptic Manager. Couldn't open.
Things I've already tried by reading through forums -
1.I logged in through root shell prompt and ran updates, reinstalled ubuntu-desktop package
2. Logged in through shell prompt changed back permissions of the file I had changed.
3. Did a recovery mode boot and selected the repair broken packages option
4. At login time did ALT+CTRL+F1 to go to shell, logged in successfully then launched startx. Wanted to install lightdm through synaptic manager, but synaptic manager wouldn't open. Just the same way as in my last proper ubuntu session. I open it, only the waiting icon appears for my mouse pointer and then just nothing
Can someone please help me?