hi guys,

just only today i experience a strange issue on my dual-boot system running lubuntu 15.10/windows xp.
i start the pc, it passes from the grub menu(with big fonts!) but after that it seems that gets on suspension-like state. keyboard and all works but my screen is black and the monitor's led is blinking like as it's on suspension-mode.
i tried to see if windows work and yes they do!
then i tried to go in recovery mode but it's impossible to go from there as the fonts are unrecognizable!
(i have greek fonts and in that menu they seem as rectangles)
i would really appreciate anyone's help please.

thanks

ubuntu 15.10 is dead, end of life:
https://wiki.ubuntu.com/Releases
that might or might not be the reason why you experience this, but before attempting to help it's better to reinstall first.
please use an LTS version.
if you have to save data first, have you tried booting into recovery mode?

yes as i have mentioned it's the same even in recovery mode.
in recovery mode i cannot do much because i canot read the fonts as they are like rectangles!
my concern of course is the data i have... i wouldn't mind reinstal, update or anything.

that sounds pretty serious.
i suggest you boot from a live usb and copy personal data off the hard drive (to some third external storage).
then have a good think what might have gone wrong, because i don't think we have a chance of investigating.
then re-install, preferably Lubuntu 16.04 LTS.

i decided to try reinstalling lubuntu on top with my "alternate iso" but without changing the partitions etc so as to hopefully keep my "home" files!
i am not sure though how to do it...
should i go "manual" partitioning or what?

yes.

in manual then,
i know which one is the partition i have "lubuntu" but as i go with it,
i have to choose again the file format and the mount point since my old values are not shown!
there was only one partition for "lubuntu", one for "swap" and of course another one for "windows" so i guess i should put "/" as mount point... right?
"ext4" for file format i am sure for that one.

If you have only one partition for Lubuntu, you need to get any data you want from your /home and/or other directories copied somewhere else before you install another version or it will all be overwritten. And yes, the "/" is the symbol for the root filesystem for the system partition and ext4 would be a good filesystem to choose. You would need to select the specific partition on which your previously had Lubuntu sda2, sda3 or whatever it is.

i was going to reinstall the same version so as not to lose my home data if that's possible.
then i can save my files and install a new version!

Have you tried to ssh into the computer from another computer? Perhaps you could get at your data that way. Otherwise, I second the live USB suggestion.

i have already installed the 16.10 lubuntu from a usb grive. i chose the first option to upgrade and keeping my "home" folder files.

everything was seem and working fine on "live" but as soon as the installations finished i got an error of "apt-clone".
i am not sure if this is serious.
as soon as i reboot i got the screen resolution to 640x480 and it cannot change from the "screen settings" as there are no other options available.
i tried to run "system profiler and benchmark" and i noticed that everytime i click on "filesystems" and "input devices" it crashes...

so i got any files i needed and reinstalled 16.10 without keeping my old files!
it worked perfectly until now with no errors!

thank you guys for your help