The computer worked fine for a while, until I decided to install a couple of games. I'm not sure when [It's been less than a week], but the computer decided to start acting up. The power switch is usually turned off, and when I turned it on, then pushed the power button on the computer, it loaded the BIOS screen, then the moniter turned a green colour, then grey and stayed that way until I restarted the computer. The next time I booted up the computer, it loaded the BIOS screen, the Windows XP loading screen, then turned green again. I restarted the computer and it booted successfully. The next day, I turned the power switch on, and pressed the power button on the computer, it started booting up, although I noticed there was a delayed amount of time before the motherboard gave a beep, but the moniter stayed black. I restarted, but once again, it just beeped after a while and the moniter stayed black. I turned off the power switch [I know it's bad to do that to a computer while it's powered on, but I had no choice], then turned it on and it successfully booted. Every day since then, the same problems have occurred, and I have had to turn the power switch off then on multipe times for the computer to start successfully. Sometimes it successfully boots until the desktop, but then freezes. Today, when I tried to turn it on, it got to the desktop then froze, and after that refused to boot properly anymore. The computer boots, but the moniter stays black. Restarting does not work, nor does turning the power switch off and on. I wanted to boot into safe-mode, but since it doesn't even boot properly, I cannot do that.
Does someone know the problem I'm experiencing, and a solution? I am not good with computers, and I do not really want to open the case or anything. But if it comes to that, I'll do it. Thanks for your time.