How does an investment by a Private Equity differ from Venture Capitalist?

what is the method followed by both the parties?
i mean what is there style of investing?

A venture capitalist is someone with money that is invested in a number of private firms. Their funding is usually tied to other issues. In particular, there are conditions where the VCs may get more control over the firm. The VC relationship is often an active one -- with VC employees being put on the board of directors and the VC firm taking on the roll of advisers.

Private Equity is equity sold to anyone prior to going public. VC firms purchase private equity. But others can invest in private equity as well. An insurance company may do it to diversify their portfolio. You frequently see a larger corporation invest in the equity of a start-up when there is a strategic agreement between them (e.g., Merrill Lynch bought 30% of Bloomberg's private equity in the mid 1980s -- and Bloomberg developed analytical tools for ML. Bloomberg later bought back the shares.

Not all private equity adds the same kinds of constraints that VC adds.

Two different names for the same concept.

One of the biggies in the news recently is Blackstone Group. They managed a buy-out of the publicly traded Equity Office Properties REIT. Previously they had gone in with HP to buy out Computer Sciences and before that went after Freescale Semiconductors (last I heard Kohlberg Kravis Roberts were poised to spoil that one). These are not VC (Venture Capital) infusions. Fat cats like Carl Icahn and Boone Pickens put up personal or personally-secured cash to buy interest in or take over already existing companies. Sometimes things aren't taken private, Edward Lampert's ESL holdings who did major financing, and still holding a large stake last I heard, in Sears Holdings, the KMart/Sears merger product, is a similar example.

The link below is a starter on Venture Capital, a distinctly different breed of dog.

VC tends to invest in start-ups while PE more often than not refers to investment in established companies.

Different stage of investing and telent: PE are more late stage, with leverage capital, typical financial engineering, VCs are early - mid stage, company builder, riskier capital. VCs typically looks for 10x of return where PE with 3x is good since VC can not deploy a lot of capital