Raspberry Pi 3 B -Can not connect via LAN cable -PLEASE help

[guzu]

Hello.
First of all, this is my first post here, so sorry if I do anything wrong

I have a Raspberry Pi 3 (first time using one of these) and i managed to install the OS on a SD card and run it on the raspberry.
I connected to it via Putty>vnc viewer (I don't have a hdmi monitor, only a laptop)
Everything worked fine. i connected to it multiple times.
But then I turned it off (using shutdown) and now I can not connect to it anymore.
It does not get an IP address (I scanned using advanced ip scanner)
The LEDs are on (red always on and green blinking every once in a while)
When i plug it in my laptop's LAN port a new LAN connection appears in network manager.
I reinstalled the Raspbian on the SD card but still can't connect.

Can you help me in any way to connect to the Raspberry please?
If you need any more info, just ask.

Thank you very much in advance.

[guzu]

So after a lot of head scratching I found out that the board got a new IP.
Instead of being 192.168.137.81 it was 169.254.38.288
I did not change anything and did not change the ip on any card.
I used a monitor to find out the new ip then changed the ip on my laptop and i could connect to it again.
But now the same thing happened again. The IP is no longer 168.254.38.288.

Can anyone tell me why this is happening?
And how to find the new IP without connecting it to a display or monitor?

Thaks

[fruitoftheloom]

So after a lot of head scratching I found out that the board got a new IP.
Instead of being 192.168.137.81 it was 169.254.38.288
I did not change anything and did not change the ip on any card.
I used a monitor to find out the new ip then changed the ip on my laptop and i could connect to it again.
But now the same thing happened again. The IP is no longer 168.254.38.288.

Can anyone tell me why this is happening?
And how to find the new IP without connecting it to a display or monitor?

Thaks

If you setup Connection Sharing on the Windows Laptop (differs depending on version) then that should alleviate issues

The Raspberry Pi should be left as standard as Windows will issue an IP address.

[guzu]

Thank you very much.