Not right today

My computer is behaving screwy again.Just two weeks ago, it refuse to boot up and last week, the it could not detect the internet connection even though the wires are connected and my dad certainly did pay the cable company on time. It several power cycles to make the compoter realise that the modem was on. Today, the colling fan was making a lot of noise. I decided to open up the comp to see any hardware problem but fortunately there isnt. Again it took me another power cycle to make the computer start silently again. Some other hardware problem I can't get to fix is the dumb scanner/printer. I bought a new ink catridge to replace the old one last week. Installing it was easy. All I had to do is open up the cover and replace the old catridge with the new one. After that, thats when things go wrong. I know that I've bought a correct catridge for the printer(it's basicly a lexmark X300 series) and I've insert the catridge properly but now that damn thing thinks the cover s still open even though I have properly close. Now not only I cannot print, I can't even scan any image all because the printer/scanner think it's cover is still open. I guess this is what happen if you combine a scanner and a printer together. If one part of the device fails, all of it fails. I think I install my old still functioning scanner f I want to scan a pic.