No display after cleaning CPU

[JEIson]

my computer kept dying out after being on for a short time. took it to a shop and they said it would not be worth fixing. I opened it up and saw that the heatsink was full of ****, so I cleaned it along with the cpu, added compound, put it back together, computer comes on, will not load. ordered a used cpu, switched the cpu, and now there is no display at all. what could the problem be & how do I fix it?

 

[Tmagic650]

The replacement CPU could be bad, or the motherboard is toast. The CPU overheating could have damaged the motherboard...

 

[JEIson]

bad motherboard

if the motherboard is bad, how does that affect the rest of the components? would it damage or destroy them?

 

[Tmagic650]

The rest of the components should be okay. How old is this computer, more than 4 years?

 

[JEIson]

at least 5 yrs. old. I am beginning a pc repair course. should I keep the pc and maybe use it for future parts, or do you think their is a possible fix?

 

[Tmagic650]

I thought it was that old... Could be a bad power supply, so keep it and see if you can fix it for practice. The parts are of no real value at this point... Computers go out of style every year or two. This one of mine was a year old last October