You earn £50K but have a mortgage of £400K (debt) on a house. Why is that you are not a basket case? Because the house is an asset that you hope (and lenders believe) will gain in value. Even if it doesn't, the mortgage payments will be similar to or less than the rental you would pay on a similar property. People with money lend you the £400K on the basis that you pay interest on that loan.
Similarly, the $50bn of debt has been used to purchase assets - VMWare for example - that may gain in value (if someone wants to buy them). However, unlike your mortgage which is 8 x your revenues, the Dell debt is far less than their revenues. In the meantime those assets will be expected to earn their keep by generating revenue. And it seems they are if, as claimed, their positive cash flow is able to generate $14bn this year. Dell is probably charged 5% for the privilege of borrowing $50bn but it seem the assets acquired are generating cash at a greater rate.
He probably wants to go public to convert some or all of that debt (which *has* to be repaid and could be called in) into equity from new shareholders (which doesn't have to be repaid and can't be called in). Much better from a manager's point of view but not necessarily so good from a shareholder's perspective. Moreover, that debt will have been borrowed on the basis that it is used for specific purposes. Equity funds can be used more flexibly so long as the company keeps to the business model outlined in the prospectus. Again, much better for the managers.
So the battle is to show prospective investors that their money is safe in Dell. That they will more than get their money back. That they are generating $14bn in profit on $97bn in revenue and that is could be better if they were not paying interest. That there is room to make more acquisitions using shareholder money to make even more profit.