|If there is nothing wrong with the hardware on your computer, you should get video while booting, before Windows or whatever operating system is supposed to load from the hard drive, no matter what, regardless of whether the hard drive or the operating system works properly.|
If you have the monitor plugged into the correct video port, the "plez chek signal cable" message is generated by the monitor itself and probably indicates it is not receiving any video signal from the computer. The message is probably the same when the monitor is not connected to the computer at all when the monitor's power is on.
Usually when you are getting no video from the computer there is nothing wrong with the video adapter - usually something else is wrong - obviously your monitor is working or you wouldn't see that message.
If you have not been messing with anything inside the computer case, and have not moved the computer from one place to another, just before this happened, then this is the most likely cause of your problem......
Failing power supplies are common and can cause your symptoms.
Check your PS.
They often partially work, fans and hard drives may spin, leds may come on, yet you may get no video and the mboard will not boot all the way.
See response 4 in this:
If you can borrow a power supply from another working computer, try connecting that.
If it is failing, you can usually replace it with any decent quality standard sized standard ATX PS with the same capacity or greater.
Standard (PS/2) power supply size - 86mm high, 150mm wide, 140mm deep, or 3 3/8" h x 5 7/8" w x 5 1/2" d , or very close to that, though the depth can be more or less for some PSs.
Don't buy an el-cheapo (in quality) PS.
See response 3 in this:
Note - I may have mentioned Coolermaster in that - I have recently found some models have only a 1 year warranty, some are known to have premature fan failures, some are known to develop failing electrolytic capacitors.