NEW YORK — Hewlett-Packard Co. said Tuesday that it had taken an $8.8 billion accounting charge, after discovering ‘‘serious accounting improprieties’’ and ‘‘outright misrepresentations’’ at Autonomy Corp., a British software maker that it bought for $10 billion last year.

It is a major setback for a struggling HP. The charge essentially wiped out its profit. In the latest quarter, HP reported a net loss of $6.9 billion, compared with a $200 million profit a year earlier.