After a recent software update (possible to kernel 3.13.0-49), Ubuntu Trusty no longer displaying Launcher & top status bar properly on a very old Dell using 32 bit Ubuntu Trusty. I used to use xorg-edgers ppa on it but I took it off about a year ago while back when it was no longer needed as Trusty did the display properly (or it might have been as it no longer worked properly). I've tried putting the ppa back again & upgrading but still the same. Also, the mouse cursor moves but clicking it on an icon's area does not work. Unfortunately I used Ubuntu Tweak to remove old Linux stuff. Any ideas?
I suspect the problem could be a quirk in your video card.
I have a older Dell (approximately 9 years old) that I bought used, and on which I have run Ubuntu exclusively for quite a few years. Starting with Ubuntu 12.04 I found the Unity Dash was unusable. (When I clicked the Dash button, the screen would flicker but none of the Dash overlay would appear on the screen, so there was no way to select any icon in the Dash at all.) Back in 12.04 you could login using Unity 2D, which avoided the bug in the video card's firmware. By the time 14.04 was released, Unity 2D was gone, so I knew I wouldn't be able to upgrade my machine if I wanted to use "stock" Ubuntu.
SO I copied Ubuntu 14.04 to a USB stick and carried the machine to a local computer repair shop and asked them for a cheap generic video card (using a different chipset, just to be sure). The folks at the shop installed their video card and I booted from the USB stick to test it. I rejected a bad one, but ultimately got a working card that works fine, and the replacement cost me very little.
Another even cheaper option (if your Dell system works this way) might be to try the Intel video built into the motherboard. On my system, I have to remove a plastic cap blocking the video port and also activate the onboard video in the BIOS.
Nowadays the limited RAM in my old machine (4 GB maximum) has begun to become more of an issue with modern RAM-hungry applications, and there's not as easy a workaround... except that your local computer shop might sell you a four- or five-year-old machine with a more modern upgradeable motherboard and processor.