If back to school sales have you thinking of buying a home computer at last, or getting a faster new one with more features, it may be a good time. Steve Rouze of Newton repairs home computers, and says the costs are as low as they’ve ever been. The big companies have paid off their costs for research and development and so can sell computers so cheaply, they’re almost a disposable appliance. That’s not so good for a repairman like Rouze, but he says it’s great for consumers who’ve held off getting a personal computer or upgrading to a more powerful one. The digital repairman says new printers are priced so low, they almost cost you less than you’ll spend on the ink cartridges to put in them. Where once technical problems and confusion about the cords and connections gave owners headaches, Rouze says the worst problem for many computer owners today is…catching a virus. He says it’s hard to keep up with them all, there are so many, but mentions a virus called WIN-DOS he came across recently that “kind of cripples” your computer. The best defense is a good immunization, says the repairman, with a brand-name anti-virus program like Symantec’s Norton. He calls it “sweet” and says he recommends it and puts it on all the computers he works on. Rouze says the program is installed, configured, and then you can forget about it. Best thing about a good anti-virus program, he says, is that it will go on the Internet and get its own update so it’s ready to tackle the newest viruses going around. Rouze runs Avatar computer repair in Newton.