I shouldn't run McAfee or Norton when you only have 256MB memory. But that's your choice. Better add memory or switch to NOD32.

Anyway, go into Control Panel, and set your virtual memory to "System Managed". That should help against that error message about low virtual memory.
http://support.microsoft.com/kb/308417 tells you where to find it; it's a few clicks deep.

And I think that message about unclickable children is something caused by something on that site, not on your PC. Can you tell exactly when you get it, in such detail that anybody following your instructions (go to ..., click here, fill in this, click there, ...) can see if he gets it also. That's the only way for us to check.