Computer problems, including with virtual memory?

Please help. I am computer illiterate, and don't know what half of the terms I'm dealing with even mean. Sometimes I will get the message that "...ran out of memory at line 56" or something like that. Other things like "...does not have enough virtual memory to access..." I think that my computer is already operating at maximum virtual memory...I think. Lately the screen has been freezing as well, and I'm not even sure that there is virus protection on this computer. I already tried using the help thing after clicking the START on, but it didn't help at all. Please, if you even have a vague idea of how I can fix this mess, please please tell me. Thank you in advance.