So to not keep you guys feeling abandoned, here's a quick update: it has been discovered that the reason my computer had been sufffering those failures is the motherboard itself, which is an old model and it coudn't handle anymore, so I'll have to replace it and the hard drive which also stopped working, but don't worry I backed up all my files in an external hd to make sure that I won't lose anything.
I'll probably manage to buy the new motherboard and the hard drive this weekend or on the next one, I'll let you guys updated once I get any furher news.