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In short, my question is: is the appearance of green squares for a second during the boot process (for a picture, scroll down) a symptom of a failure for a particular component? That is, can I, without further testing, know which component is faulty?


About 2-3 years ago, I assembled my own PC. Because of that, all components have warranties with different vendors/shops all over town. The computer recently broke after me having cleaned it (it wasn't my first time cleaning a PC, nor even this PC in particular, though I can't guarantee that it's not my fault). At the first boot afterwards, the power fuse for the room went down and upon further inspection it became evident that the PSU for the PC is gone. Luckily, it was in its warranty period, and it was changed. However, now I am running into the issue described above. I don't want to test further by removing components one by one, because I believe that this would increase the chance of other components failing, too (is that correct?). Since the components have warranties with different vendors, I can't rely on any of them to do the diagnostics.

At the first boot after the changed PSU, a warning message came up about the BIOS not being in a good state, or something related, I don't really remember. Could the whole issue be solved by a simple BIOS flash?

Image of the behavior described:

green rectangles on screen during boot

I can also upload the whole video of the boot process, which lasts a few seconds, if necessary.

Components information:
CPU - Core2Quad Q9400
RAM - 4 x 2GB Kingston 800Mhz
MB - Asus P5Q-E
GPU - Palit nVidia 560Ti 2GB
CPU Cooler - Xigmatek HDT-S1284
Original PSU - CoolerMaster GX 550W
New PSU - CoolerMaster Silent Pro M 600W

No components have been overclocked, or tampered with during the lifetime of the PC.

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Are there any other ill effects except for these green rectangles flashing for a second? If not, then it is probably because your video card is not being fully/properly reset during POST, I wouldn't worry too much about it. – haimg Jun 17 '12 at 23:25
I haven't tested much, because of the reasons cited above, but entering BIOS works fine and the PC runs supposedly normal (without OS, since I've disconnected the HDDs) for a few minutes at least. – K.Steff Jun 17 '12 at 23:27
@haimg It appears this was the issue indeed. I've run many tests since and everything is OK. If you'd write an answer, I'd mark it as accepted. Thanks. – K.Steff Jul 1 '12 at 15:48
up vote 1 down vote accepted

If there are no other ill effects except for these green rectangles flashing for a second, then it is probably because your video card is not being fully/properly reset during POST. I wouldn't worry too much about it, because Windows (or any other OS) will re-initialize video hardware again during its startup.

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