As previous question,
memory has now gone up to 2.03GB or 70%.
any help please.

cg, July 2016

Thanks ELECTRO much appreciated, and to other people that answered my question.

cg, July 2016

Your machine is working fine
You worry about something that you need not worry about

Relax..., July 2016

70% of memory use for about 2 Gb of memory use indicate that you have 3 Gb of RAM.
If you have a 32 bit OS, it's about as much as you can use. At most, you can use 3.5 Gb of RAM. If you have any Pentium, it's a 32 bit CPU and you can't install a 64 bit OS.
If you have a 64 bit CPU (intel i3, i5 i7, or ATI made after 2005) AND a 64 bit OS, you may start thinking upgrading that to 6 to 8 Gb. You'll see a solid performance increase.

In a modern computer, running a 64 bits OS and just a few basic applications, using around 2Gb of RAM is normal.
Normally, the OS tries to keep as much of it's code loaded into RAM to be more responsive.
Add your anti-virus and some other background stuff, and your memory usage rapidly climb. Now, add any application in use.
Having a memory use of about 80% to 90% is NORMAL !
Unused memory is wasted memory.
If needed, the OS will quickly unload unused code and data to make room for a memory hungry application as the need arise.
I'm using a P4 based computer and I can get memory use at 95-98% without any problem.

Electro, July 2016

Seems OK but the memory in use will depend on what the machine is doing? If you have no idea what you are looking for, why not post a question that describes the problem you actually have, rather than jumping in with a possibly irrelevant statistic.

My machine is an i5 PC with 8G RAM and Windows 10. I am currently running just Firefox(plus the usual background applications).

I try not to install any "browser helpers" "toolbars" "registry cleaners, etc. and actively remove any such crap.

I am using Windows Defender for antivirus. My machine currently reports about 1.7G in use.

HTH, July 2016