Any way to optimize 10 machine without having to go and maunally disable services on 10 machines
Use GPEDIT.msc to configure a GPO that disables the unnecessary services/processes. Then manually copy it to each machine, apply it and restart (you need to do this manually because you have no domain, only workgroup). You can do this remotely.
Also, configure the GPO to prevent a user from installing or running any additional apps, with such little RAM you don't want users running junk in the background. Also, the biggest problem you may have is with AV. You may need to tweak the realtime scans to reduce the amount of memory used. I find that on average AV uses 40 - 300MB RAM, too much for your machines.
Another thing to look out for is Firefox, it uses a lot of additional RAM when compared to IE, so rather use IE if possible. Also, Outlook is a RAM hog, easily using 150+MB per user. To reduce this disable MS Word as the default editor.
Download Autoruns, link below, and disable everything that runs at startup that you do not require. Autoruns is similar to the MSCONFIG utility, but lists every single item set to autostart, including IE plugins etc.
From the same site run VMmap to view exactly which applciations are using memory and then stop them....
http://technet.microsoft.com/en-us/sysinternals/bb795533.aspx
Good Luck!