So I've seen how the Dell Inspiron 1545 seems to run at a slightly high temperature. I Generally average in the 50-60 degree C range, although for some reason it's behaving right now at 46 C...
A search online showed me these results, and I wanted the opinions of people who know what they're talking about. Is this a safe idea? I don't want to input anything in my computer that would screw it up.
Here is the explanation and a possible solution for your laptop. It's the BIOS. Most laptop computers are designed specifically for Windows. Therefore, on many models, the BIOS does not control the fan, as is normally the case, but they depend on Windows Power Management. Obviously, Ubuntu is not windows. Therefore, the kernel must manage the fans. Sadly, a majority of laptops do not need this, so the default Ubuntu setup doesn't account for the minority, and far be it for the designers to make all easy and automatic like, detection wise. So this is left up to the user to try and fail to find an answer in the vast twisted jungle of hostiles and beasts known as the Linux community of da interwebz.
Fret not, however. You just need to modify GRUB2, which is what boots Ubuntu, essentially, and input a kernel command that will tell it to manage your fan. The following should work. If it doesn't, sorry. But it really should work.
In Ubuntu (version 10.04 and up)...
Type (without quotes, obviously) 'gksu nautilus'. Push Enter (or Return).
Enter your password, if necessary.
In the new administrative-be-righted Nautilus File Manager window that has just opened, navigate to 'File System' in the left side panel, then navigate to the 'etc' folder, then navigate to the 'default' folder, then open the 'grub' file. Good.
In the new gedit text editor window that has just opened up, look for the line that reads: GRUB_CMDLINE_LINUX=""
Now, precisely between the two quotes, without any spaces, copy and paste this exactly: acpi_osi=\"Linux\"
The line should now look like this: GRUB_CMDLINE_LINUX="acpi_osi=\"Linux\""
Save the file and exit the gedit text editor.
Now, open the Terminal (Applications>Terminal).
Type: sudo update-grub
Press Enter (or Return) and wait...
Has the text stopped moving? If so, you're almost done.
Exit the terminal.
Now the correct kernel/fan behavior has been activated and the fan will work as it should and your excessive heat Ubuntu laptop problems are solved. You're cured. Do something else. Carry on. Don't worry. Be happy. You're welcome. Good luck. Goodbye.