You say you’ve been longing for the stock market’s good old days, ’90s-style? Then this is your day.

In just a few weeks, if all goes as planned, you could own the latest hot Internet stock.

Monday, Google said it would charge $108 to $135 for its first publicly traded shares, expected to be offered by the end of the summer.

Google has a great product, no doubt about it. I haven’t used any other search engine for years. Lots of Internet users don’t even know there are other search engines.

But will the shares really be worth so much?

Well, they’ll be worth whatever investors are willing to pay. Google appears to have set a high price based on ample evidence investors are drooling over the stock.

But investors don’t drool forever, as we saw when the tech-stock bubble of the late ’90s burst in 2000. The Nasdaq 100 index, which is packed with technology stocks, trades today around 70 percent below its March 2000 peak.

While Google is not yet publicly traded, it does have privately held shares — 268 million of them. If it earns as much in the second half of 2004 as it did in the first, it will make about $1 per share this year.

Assuming the company sells shares at its minimum offering price of $108, the stock’s price-to-earnings ratio will be 108.

That’s pretty high given that the long-term average for big-company stocks is around 15. Today, lots of pros say the norm is about 20, adjusting for factors such as low inflation and interest rates.

At $108, Google would sell at more than five times the price it would with a “normal” P/E of 20.

There’s plenty of precedent for this. In the late ’90s, lots of tech companies went public before they made any profits. That meant their P/E ratios were infinite.

Even today, some other tech stocks have sky-high ratios. Yahoo, for instance, traded Monday at about 113 times earnings. Of course, Yahoo shares are down more than 20 percent since late June.

So if you are attracted to Google, say this out loud right before you call your broker: “High P/E means high risk.”

That’s because a high P/E stock has to compete with others that are cheaper. With a 20 P/E stock, you pay $20 for every dollar in earnings. With a 108 P/E, you pay $108 for every dollar in earnings.

Why would you pay more than five times as much for a dollar of earnings? You wouldn’t — unless you thought the company would make more in the future. In other words, to justify $108, Google’s earnings would have to quintuple.

If they don’t, investors will eventually lose heart and the stock price will fall until it reaches a more normal level. If earnings doubled to $2 per share, the normal share price would be $40. The company would be doing great, but people who paid $108 for the stock would have lost about 63 percent of their investment.

Google’s earnings have doubled during the past year, but no one knows how long the company can keep that up.

Google investors will face some other risks as well.

First, the company will be tightly controlled by its two founders. They will own a class of supershares, not available to ordinary investors, giving them 10 votes for every share instead of one.

That’s OK so long as the founders continue to excel. But if they falter, ordinary shareholders won’t have the voting power to force them out.

Then there’s the problem of competition. Microsoft is working on a search engine, as are others. If Internet users desert Google for a sexier alternative, the company could crater.

Don’t get me wrong — I’m not predicting that. The fact is, winning stocks tend to be risky.

But if I were putting money on Google, I wouldn’t bet more than I could afford to lose.