When the campaign organization of Republican presidential candidate Marion G. (Pat) Robertson was in debt last month, records indicate it sold its main computer system for at least $100,000 more than it cost to a shell company in Denver whose only identifiable official is a Robertson campaign aide.

The nature of the transaction, which Robertson's campaign refused to discuss with The Washington Post, raises questions about whether it was a legitimate business deal or an illegal campaign contribution by the person, persons or firm that paid the $337,500 deposit listed in campaign records. Federal election laws do not permit corporations to contribute directly to campaigns. Individuals are limited to contributions of $1,000 or less.

The campaign committee, Americans for Robertson, bought the computer system in January for $233,480 from a longtime Robertson associate. R. Marc Nuttle, Robertson's campaign manager, said last week that he was in the "process" of selling the system and leasing it back. In a report to the Federal Election Commission, the campaign said it received $337,500 on Sept. 30 from a Denver computer firm, listed as "Computer Futers Ltd.," for "deposit-sale of fixed assets."

There is no telephone listing for such a firm in Denver and no record of it in the state of Colorado's records for corporations, partnerships or sole proprietorships. There is a record for a Computer Futures Ltd., at the same address listed in the campaign report. That name was reserved on Sept. 2 by Clarence A. Decker, a Denver attorney who is one of Robertson's regional campaign directors, but no incorporation papers had been filed as of Oct. 15. The address listed in the campaign report for "Computer Futers" is that of Decker's law firm.

Decker, in a brief phone inter- view, said he is the registered agent for Computer Futures but declined to answer any questions about how the firm came to buy the computer or whether Computer Futures is an operating business. He referred all questions to Nuttle.

Sharon Snyder, an FEC spokeswoman, declined to answer questions specifically about the Robertson transaction. But she said campaign committees usually are only allowed to sell assets for more than the contribution limits under special circumstances. The commission has issued several advisory opinions against such sales because they might be viewed as fund-raising mechanisms.

In one case last year, the sale of an asset was permitted as long as the buyer was someone in the general public, rather than a campaign supporter, and the sale was for fair market value without a lease-back arrangement.

It has been reported that the Robertson campaign attempted to sell its computer system a few months ago to a group of supporters for $1 million and then lease it back. The plan, to have 20 individuals put up $50,000 each, fell through.

Robertson campaign officials declined to return a series of phone calls on the issue over the past two days, including calls yesterday. Campaign secretaries said neither Nuttle, the campaign manager, nor Constance Snapp, the campaign press secretary, was available.

Buying a large computer system is considered unusual in campaign circles because it is so expensive. Most campaign organizations purchase their direct-mail computer services from specialists outside the campaign.

Americans for Robertson bought the computer system last January from George F. Border of Norfolk at a time he was settling a dispute over funds owed him by some Robertson-affiliated groups.

Border, who did fund-raising, had purchased the system -- an IBM computer, software and equipment to perform direct mailing -- a year earlier for about $600,000, he said in an interview.

The campaign picked up the $233,480 balance Border's firm owed on the system to a local bank. Border said that he had been assured by the accountant representing Robertson that the price was very close to the fair market value of the system.

"I can assure you it was the market at the time," he said. "Unfortunately, it wasn't a sweetheart deal for me, and I don't think it was for them."

At the same time, Border and representatives of Robertson were negotiating settlement of a dispute about money owed the Border firm by the Freedom Council. That group was founded by Robertson -- and funded in large part by his Christian Broadcasting Network (CBN) -- to get Christians involved in politics.

Steve Davis, who was Border's controller, vice president and negotiator, said Border was prepared to sue the Freedom Council, Robertson, and CBN if a satisfactory settlement had not been worked out.

CBN and the Freedom Council are being audited by the Internal Revenue Service to determine whether they violated the law by using tax-exempt funds to aid Robertson's political ambitions.

Davis said that as part of the settlement between Border and the Robertson groups, the campaign took over the Border firm's office lease as well as the computer system payments. Several of the firm's direct-mail specialists were later hired as campaign staffers.

Nuttle said in the interview last week -- before the report listing the $337,500 payment from the Denver firm was filed with the FEC and before the campaign ceased answering questions -- that he was in the process of selling the system. "I'm going to resell it probably, and try to get some cash out of it," he said. "I'm going to get some broker to sell it and take a lease back and get the cash out. In fact, that's in process now." He said the system was worth about $600,000.

It is not clear how that value relates to the $233,480 fair market value Border said had been placed on the system earlier this year. Because of rapid technological advances, experts said, used computers depreciate rapidly in value -- rather than appreciate.

The $337,500 receipt on Sept. 30 from the computer transaction was included in the more than $11 million the Robertson campaign reported raising over 14 months. The report shows that during the same period the campaign spent $11 million, had $233,000 in the bank and debts of $814,000.

A review of the report shows that the campaign owed money to several vendors and was behind in rent and utility payments for its office in Chesapeake, Va., and owed more than $70,000 to its staff for unreimbursed expenses.

Wayne Bailey, a South Carolina investor, told The New York Times last week that Nuttle, seeking cash for the campaign, had approached him about becoming part of an investor group that would pay the campaign $1 million for the computer system and then lease it back. He said he wrote the $50,000 check to the Robertson campaign in August, but it was returned because the rest of the investor pool could not be filled.

Bailey said earlier this week he did not know how the $1 million value on the system had been determined. Bailey said he was asked by the campaign to forward all inquiries about the sale to Nuttle.Special correspondent Susan Kelleher in Denver contributed to this report.