HEWLETT-Packard (HP) has introduced a new series of low-priced Intel 486-based personal computers (PCs). The HP Vectra 486VL series features accelerated graphics and enhanced 486 performance. The PCs offer an industry-standard architecture (ISA), and standard models include a 486SX/25, 486DX/33 and 486DX/66. The SX/25 and DX/33 models have a choice of 120-megabyte (MB) or 240-MB hard disk drives, and the DX2/66 comes standard with a 240-MB hard disk. Four MB of random access memory (RAM) comes with all of the machines in the series, and this is expandable to 32 MB. An 128-kilobyte second-level, write-back memory cache is an option. Expansion options for all the 486VL series models include four mass-storage shelves (two front-accessible) and four ISA slots. The systems also offer a standard 3.5-inch floppy disk drive, plus a 5.25-inch floppy disk drive or CD-ROM support. Servicing is easy because all components can be removed easily: the covers can be detached by unlocking two latches in the front of the boxes. Only one screw (the one that holds the motherboard in place) needs to be removed when servicing. HP said one of the key features of the 486VL series was that it was ''environmentally friendly''. Plastic parts are marked with a code that indicates the kind of plastic material used, which makes parts easier to recycle. The lowest price in the HP Vectra 486VL series is $12,000. This is for the basic 486SX/25 with a 120-MB hard drive and four MB of RAM, and it does not include a monitor. The DX/33, with a 120-MB hard drive, costs $15,719, the one with a 240-MB hard drive costs $17,911. The DX2/66, with a 240-MB hard disk, costs $22,487. All come with Windows 3.1, MS-DOS 6.0 and video drivers pre-loaded. A three-year warranty - standard for most HP PCs now - also covers the 466VL series. with a next day on-site warranty (a guarantee that HP will fix a faulty machine at the owner's premises within one day) covering the first year. During the second and third year, the machine would have to be taken back to HP for repairs.