Rewinding back to what @malwaredpc stated, what you could also do is:
- Boot using your original install UM ISO/DVD/USB stick;
- Select LIVE (instead of INSTALL on the language selection screen) and BOOT;
- Once booted and logged in the GUI, CTRL+ALT+T opens up a terminal;
- in which, write:
$ sudo fdisk -l
Which should then display something like:
Device Boot Start End Sectors Size Id Type
/dev/sda1 * 2048 39845887 39843840 19G 83 Linux
/dev/sda2 39847934 41940991 2093058 1022M 5 Extended
/dev/sda5 39847936 41940991 2093056 1022M 82 Linux swap / Solaris
Depending on what it says under /dev/sd, you’ll want to recycle that value in the next command:
$ sudo fsck /dev/sdXX
Based on the previous output the proper command would then be $ sudo fsck /dev/sda (Yes, no need to add the number at the end, just check the whole HD by specifying just it’s letter)
6. reboot
GO or NO GO.
If GO, of course, that fixed it, if NO GO then you need to move onto your next plan.
This doesn’t take much efforts and you should already have everything handy to make it happen.
Also, when the fsck process is done, and before your issue the reboot command, issue:
$ dmesg
and check for any SMART errors or anything in red that points to your HDD (Which would indicate it’s the problem).
Hope this helps,