If you bought more ram to run aside the current memory fitted to the laptop.
You should of checked the frequency in Mhz that the old ram was running at and what it`s latency values were set as for the running speed.
If it`s the case then it is likely that the existing ram along with it`s latency timings cannot operate at the same frequency and timings of the new ram.
You should also check that the voltage requirements of the old vs the new memory sticks are the same.
A tip here is if you push memory to a higher operating speed. two things may manually have to be adjusted, than leaving the bios/ motherboard to auto detect them.
So a manual adjust of the voltage, and latency values may be needed.
The error you see is often due to a timing error between two brands or types of memory.
That can cause the boot loop when loading windows, it normally gets halfway into windows and simply resets without any error message or Blue screen of death with an error code.
Make sure if the old memory is slower, that the Memory stick is placed in the first memory slot of the z5700 laptop.
Put the second stick ect in the second slot. In the bios manually set the speed rating of the first set of memory.
And set the latency values.
If the voltage differs from the First set to the second set the higher voltage.
I say this but when it comes to laptops on most the bios is pretty basic and does not allow you to make such changes.
But if yours does then give it a try.