I have a Dimension 3000 and had it about a year. I keep getting "hang-ups" and it will have to be shut down awhile. Sometimes it will say it "has encountered a problem and must shut down" AND-- I get messages saying "virtual memory low" I clean out all the junk every 2-3 days and I have McAfee protection. I use Verizon DSL. Can anyone (in layman terms) tell me how to fix these problems?? Can I take my computer back to like it was on day one??

Thanks in advance!