Inaccurate and confusing advice given by shop staff can make it difficult to buy the right PC on the high street, a new survey shows.
Some assistants made false claims or tried to blind under-cover researchers for Computiing Which? with "technobabble".
An assistant at one branch of PC World warned that virus software could restrict children's use of computers.
In one branch of Comet, an assistant said a computer came with desktop publishing when it didn't.
Only three PC retailers recommended anti-virus software - something Computing Which? recommends with all new computer purchases.
Assistants' knowledge of video editing software was also patchy, researchers found.
Despite hit and miss advice most shops did recommend a suitable PC and roughly half were aware of forthcoming technology developments.
Computing Which? praised most sales staff for steering clear of jargon, or at least being able to explain what it meant.
Supermarket sales staff were honest about their stores' stock and advised the researchers to visit a more specialised shop.
Computing Which? also praised the advice and level of service given by staff at two independent retailers but said their PCs were up to £300 more expensive than those at the chain stores visited.
Computing Which? editor Jessica Ross warned shoppers not to be pressured into a quick sale.
"Due to the highly competitive nature of the PC sales market, advice is often geared towards a straight sale rather than finding a product to suit specific needs."
Responding to the Computing Which? report, Comet said in a statement: "We employ approximately 9,000 colleagues across 250 stores, and are naturally disappointed to learn that the Which? shopper did not receive the high level of service we strive to obtain."
PC World customer service director Jon Naylor said: "The most popular anti-virus software products we sell are internet security suites, which include parental control settings to block certain websites as well as anti-virus software.
"We think it is reasonable to assume this is what our colleague was referring to when advising the researcher to purchase 'anti-virus' software which allows parental control." ..SUPL: