my display starts to flash randomly after cpu heats (45 Celsius),in idle does not have problems.it doesn't show any kind of error it just shows black screen for one second.could it be thermo-conducting paste ? or something worse
Of the hundreds of CPU model numbers, could you provide yours?
If you were trying to be clever, and this is your processor, please confirm:
https://ark.intel.com/products/97456/Intel-Core-i5-7300HQ-Processor-6M-Cache-up-to-3_50-GHz Intel® Core™ i5-7300HQ Processor (6M Cache, up to 3.50 GHz) Product Specifications
Also provide your Operating System version.
And, provide your laptop or system model number.
I think it is premature to talk about temps (which yours seems acceptable), and thermal paste.