Comment 87 for bug 43745

Iulian, do you have the latest Dell firmware for your laptop installed? You say you use the latest Ubuntu version so this may be an indicator that this error was not solved in Ubuntu or the Linux kernel but it was solved in the Dell firmware. I'm using a Dell Latitude D820 and with the latest firmware I did not run into this problem in the last months. I even did a extreme-rebooting-test as I did to confirm the reproducability of the bug and it worked fine. So maybe there is a newer firmware available for the Inspiron, too, and it will fix the bug.

To solve your current problem you may try to boot windows once (it was reported that this fixes the clock). If you don't have windows installed then maybe a Windows boot CD (Installation disks? Live CD?) may work, too. Or try to remove the cmos battery (also called coin battery) of the laptop for some minutes to reset the BIOS configuration. This solved the problem for me even in the latest state (when the laptop stopped working at all)