I have owned my Gateway DX4300 PC (specs in link, although I'm running Windows 7 64-bit instead of Vista) since late 2009, and it's served me well for years. For the past few months; however, it would randomly crash to a black "no signal" screen, mostly while running more intensive programs like games, but it would sometimes crash on less intensive programs such as Firefox. Once it crashes, the audio stutters, then goes silent, the computer's fans continue to run as normal, and the hard drive read/write light continues to blink. At this point, I had to hold down the power button to shut off the computer. After powering on the PC, the boot process would fail, randomly crashing to a black screen. It would take several tries to reboot properly, but it worked for the most part.
Now, last week, these boot failures were exacerbated after a power outage. The computer will no longer boot to desktop normally, no matter how many attempts.
When I try to turn the PC back on, one of these things will happen:
1. PC will power on, PSU/CPU fans will spin, HDD makes sounds, but no monitor signal or POST beep. GPU fan speeds up, then slows down. The sound of the GPU fan speeding up and slowing down usually means the boot process failed, and this behavior is carried across all failed boot attempts.
2. PC powers on, monitor receives a signal, but it hangs on a black screen with a blinking cursor in the top-left corner. Very rarely, it will POST beep, but it may still fail to boot.
3. PC powers on, POST beep, and Gateway BIOS splash screen displays. It will not complete the boot process and crash to a black screen soon after.
4. PC powers on, POST beep but no monitor signal or BIOS splash. I can still interact with the computer as if it were working normally, but no video or audio. I can log in and shut down the computer blindly with the right keystrokes.
5. PC powers on, but the POST beep is one long beep and two short beeps. No monitor signal.
I've tried cleaning the dust out of the case, plugging the computer into a different outlet, reseating the GPU, reseating the RAM, booting up the PC with less RAM inserted, and none of these things fixed the issue. I replaced the CMOS battery with a new one back in August, so it probably isn't that.
I've done some research on this issue, and internet consensus seems to be that the Gateway DX4300 ships with a very weak PSU of only 300w. Most of what my PC does seems to be in line with common symptoms of PSU failure, so I'd like to hear some other opinions on this issue, and if it is a PSU issue, what's a good, budget PSU to use for the Gateway DX4300? Preferably one that is near $50 on Amazon.com, so I can use my gift card credit. Thanks for reading my rambling; I appreciate any help that you guys can give.