Requesting express RMA on DRAM?

I have been running the same hardware without any changes for several years, and all timings etc are set to auto.



I am pretty sure one of my DDR2 sticks has a problem. (info in profile)

My PC has started randomly BSODing and Windows memory checker found problems.



I ran memtest86 on the system and it failed.

I re-ran memtest several times on each of my two memory sticks individually.



Stick 1: always passes memtest (I have tested it in each of the memory slots that I have been using.)



Stick 2: consistently fails memtest (I have tested it in each of the memory slots that I have been using.)



I tried to raise a ticket for express RMA (this machine is in constant use) but the only RMA option available was standard.



Is the express service available on memory? and if so how does one request it?



I am located in the UK.



Many thanks, Hippo.