Ya the overheating problem, unfortunately, Ubuntu developers haven't solved this issue, even though they say install 11.10, well my fellow Linux friend, 11.10 won't solve your issues. I have the exact laptop you do, and it still overheats, when I use to run 11.10 or the new LTS 12.04. Apparently the Ubuntu developers don't know how to fix this fan clock bug. But I did the next best thing and bought a cooling pad. Don't spend more than 50 bucks though for this band-aid fix. I only spent about 30 for a dual fan USB cooler. Now that's in Canadian dollars though.
I have researched for almost a year now why Ubuntu has this silly laptop overheating problem and I can't find a useful thing that actually solves this issue except for installing "Jupiter" for Ubuntu, this does help a bit, by choosing things like performance levels, which include "max performance" "Power on Demand" and "Power saver". Well all this seems to do is slow down video graffics while trying to view video, or even such simple tasks as playing angry birds on facebook.(This happens on my girlfriends older Acer laptop) But seeing that you have an Inspirion 5110 this shouldn't be an issue since I have the same laptop. Mine is an i5 Intel Core.
I really hope you buy a cooling pad though, keeps temps down. In my opinion it's a toss up between getting viruses, spyware, malware infecting your computer using windows while surfing the web. I choose buying a simple cooling pad, didn't cost much, saves my laptop from overheating, and I can surf the web without constant virus attacks.
Now, as for installing "Jupiter" on your Nice Dell Laptop simply open your "Dash" type terminal and open it, copy and paste the following, one line at a time, then restart and you should have a lightening bolt icon on your top task bar, there you should be able to choose your CPU power consumption.
From a terminal, run the following commands:
sudo add-apt-repository ppa:webupd8team/jupiter
sudo apt-get update
sudo apt-get install pyjupiter
sudo apt-get install jupiter-support-eee
Like I said, it doesn't seem to matter about the version of Ubuntu you use(like the person above replied to you) when it comes to this issue, simply buy a cooling pad, and do the above. I suggested sticking with Ubuntu 12.04 LTS, since the LTS stands for Long Term Release, which is supported for the next 3 years. Kind of like Microsoft does with their support. When it comes to Ubuntu always stick with LTS, due to the fact of Long term support. As a Dell Inspirion 5110 user I really love using this O/S, Windows actually blew my speakers on this Laptop, While using Ubuntu(GNU/Linux) I haven't had a problem, also my girlfriend uses Ubuntu 12.04 on her Acer(2years old) and has never seen the "BLUE SCREEN OF DEATH" since switching to Linux from Windows.
We all have some reason to use Microsoft, but as for free goes I choose Linux, which also doesn't force you to get rid of your Main O/S, unlike Windows. If you wan't a virus free fully perfect system you could always buy a MAC, also remember the historic fact the Apple actually has part of the Linux line of code(Kernal) inside it. This is also why you don't need a virus scanner in Mac as well as Linux, Unlike Windows, which is a decent O/S but the Costly Virus Scanner Subscriptions and constant maintainance from infected root files, just doesn't add up over the years. If you have the means I suggest buying a Mac, but if you can't afford it, stick with a second O/S and run LINUX. It's up to you. But don't go on hating something you are new too, take your time then make your opinions public.
Hope this helped.