Number one PC vendor Compaq Computer Corp claims it’s extending its lead in the US market, pointing to new IDC numbers which show it held an 18.8% market share in the third calendar quarter, up 5.5% sequentially. It shipped 1.2 million desktop PCs in the quarter – 68% more than in the second quarter. Dell Computer Corp is number two in the market, holding 9.7%, up from 9.1% in the second quarter; Packard Bell NEC is third with 8.1% down from 9.4% last time; IBM Corp holds 7.9% down from 8.7%; Hewlett- Packard has 7.5% up from 6.5%. Apple Computer’s back in eighth with a 4.4% share, down from 4.5% sequentially.