City firm Berwin Leighton is completely revamping its IT system in an attempt to "leapfrog the competition".
The firm has opted to run on an Intel platform and Microsoft NT, the successor to the MS DOS operating system.
The contract for upgrading the IT system, worth over half a million pounds, has been awarded to Devon-based company Mercury Computing.
Bill Chisholm, IT director at Berwins, said: "Most legal practices are still implementing Windows 3.11. Our strategy is to leapfrog the competition and secure an advanced but stable IT platform."
The firm currently uses Novell PCs and will transfer to the new system over the next year. Users will also have access to email and to the Internet.
Pentium PCs will be connected on a local area network running on Widows NT 3.51, which will be updated to version 4.0 when it is released.
Berwins will be the first law firm to use the Lava document management system, which combines document management with document image processing and workflow.
The system will allow users to route electronic information around the firm and to monitor who views the information.
The firm is extending its existing Norwel practice management system and the Norwel desktop system will be rolled out on to all desks, along with Norwel's executive information system.
"Mercury Computing was initially appointed to conduct a detailed consultancy project, examining our needs and outlining the options in the short, medium and long term," said Chisholm. "We then appointed the company in a competitive pitch, on the basis of its technical skills, legal market knowledge and commercial good sense."
Mercury's Philip Alder said the new system was a big leap forward. "In terms of IT the firm is going from the Dark Ages to being right up to date in one go," he said.