That's where we quit trying to make the PC work and instead try to salvage the hard disk.
You can buy a USB hard disk enclosure to convert the laptops hard disk to an external disk. It's possible that all your data is still safe on the laptop's hard drive and can be accessed from another computer.
You need to confirm that you have a SATA hard disk rather than the older IDE disk. Any laptop made in the last 6 or 7 few years should be SATA.
You should have emailed your thesis to yourself every few days or used a USB flash drive to save an extra copy. The rule is if you can't afford to loose it then make three copies with one stored off site.