Samsung Galaxy S2 — google play services

Hello
Please could someone help an old numpty?
I use my s2 mainly for texting and pictures which I like to keep some on to show people or I load onto my PC, not particularly interested in net services but seems to be attached to Google.
Usually just open via coloured photo icon and all thumbnails come up, now I just get a message saying "this app won't run unless I update Google play services".
I touch the "update" button but it just goes away and nothing happens (same thing happened earlier when trying to view a YouTube video), I've turned on Wi-Fi and data.
I can get to my pictures and videos by going the long way (apps>my files>all files>extSdCard>DCIM>camera), this is a pain in the a----- and they aren't displayed in large thumbnails either.
Thanks in advance
Richard

Thank you for the response, however! I've done exactly as you suggest went onto Google play service and touched install on my phone but doesn't even install.
Tried several ways to download and install but all have failed, something is obviously amiss with my phone.

Hello again thanks for the reply, yes I did tick unknown sources, nothing happens when I try downloading just goes back to same screen.
When I try accessing pictures from "photos" icon and it says I have to update I click update it throws up a white screen momentarily then nothing else happens.
Phone keeps having a triangle with exclamation mark in at top left corner, I swipe screen down there's a message saying "an application requires attention" and Google services. when I click that it just goes away.
Thanks again for your attempts to help.

Hi
Thank you for this I've been struggling but at least now know it's not me causing this, hopefully they will release fix although I don't know how I'll know or how to get it.