Hi, I'm using an elderly Dell E521 pc with 2GB ram on 18.04. When I upgraded from 16.04, I could no longer boot normally ( kernel panic 10-APIC ). I have to use grub and select advanced options which is a nuisance. Pc is also running very slow.
I'm told switching to Mate might be a solution because of the small ram - not sure if that would cause an improvement. Also 1) would I lose my files, data, applications etc if I install Mate via terminal ? and 2) how could I reboot to install desktop if I am unable to do so at moment with 18.04 ?
Any advice would be appreciated, thanks.
Hello Langton
Question 1:
When you say "18.04" do you mean standard "Ubuntu 18.04"?
Question 2:
Do you have an external hard drive available (and does it have enough capacity) onto which you could backup your personal files (/home/your-user-name) using the Ubuntu backup program?
Your answers will help us to advise you. 
Thanks alpinejohn. Apologies for not replying quickly. Yes, it is Ubuntu 18.04 LTS Bionic Beaver.
I have a limited amount of music & photos on the pc which should easily transfer to a usb for back up. No external hard drive.
I look forward to your advice.
Hello Langton
Your hardware?
According to CNET-dot-com, you have an "intel Core 2 Duo" E6320 cpu.According to "ark.intel-dot-com" your cpu was brought to the market in Q2 of 2007. However, it is a 64bit cpu, which means as long as you are happy with the performance there is no technical need to move to a newer machine. The cpu has 2 cores and does not have the "hyper-threading" feature. Your RAM is DDR II SDRAM, which is not as fast as the most modern kind.
What I suspect is causing your problem
Ubuntu 16.04 used the Unity desktop, 18.04 uses a slightly modified Gnome 3 desktop. I suspect the Gnome 3 desktop is causing your problems, on your hardware. .What I can recommend
I have been in a similar, not identical, situation when running Ubuntu 14.04 on an AMD Athlon 4400+ cpu. Moving to Ubuntu-Mate allowed my computer to work as you would expect once more. Thus I can recommend trying out Ubuntu-Mate. I would also suggest that you consider trying MX Linux, again from personal experience. I have a Netbook with an Intel Atom cpu, which I upgraded from 1GB to 2 GB ram. MX Linux 32bit runs on it with no programmes open using only around 250 MB ram!Although I identify strongly with the Ubuntu-Mate project and community, if I were in your situation given my personal experience, I would first try out MX Linux (based on Debinan stable, with the XFCE desktop) if I had your computer.
Questions:
[1] Are you comfortable with downloading ISO-files and burning these to a DVD or USB?
[2] Do you need "snaps" (MX Linux has an excellent easy to use GUI Flatpak integration)? If you do, perhaps try Ubuntu-Mate first.
[3] Do you have enough usb sticks to make 2 backups of your data (fotos, music, etc.)
It took me a while to get back to you, I had a few "extras" in my week.
Your research is much appreciated. I was not aware of MXLinux but had a look on the web and it would suffice for my requirements. I can download the ISo files to DVD ok and I do not believe I need snap .
I'll make sure I back up everything necessary on usb.I take it I will be able to use terminal to install any other programmes such as clamtk etc....
Thanks once again.