Windows Vista's official release earlier this year gave PC sales a short-term shot in the arm, but it's unlikely to accelerate the market overall, a market research firm has said.

In-Stat said its research confirms earlier reports that the PC market in the last three months of 2006 plummeted, despite Microsoft's Vista Express Upgrade coupon program. This made buyers of PCs with XP on them eligible for a free or heavily discounted upgrade to Vista.

WINDOWS VISTA: DEFINITIVE REVIEW

After Vista's 30 January consumer release, PC sales rebounded. That upward bounce, however, is not expected to last, according to Ian Lao, an analyst with In-Stat.

"The consumers that held off on buying a new PC until Vista arrived - that demand will have been serviced by the end of the second quarter this year," he said.