Does a prisoner have a right to access to the courts in nonfrivolous direct criminal appeals, habeas corpus proceedings and civil rights actions?

The right of access to the courts applies to nonfrivolous direct criminal appeals, habeas corpus proceedings, and civil rights actions. Lewis, 518 U.S. at 353 n.3, 354-55. Where a prisoner asserts a backward-looking denial of access claim - one seeking a remedy for a lost opportunity to present a legal claim - he must show the loss of a "nonfrivolous" or "arguable" underlying claim, "the official acts frustrating the litigation," and "a remedy that may be awarded as recompense but not otherwise available in some suit that may yet be brought." Christopher v. Harbury, 536 U.S. 403, 415, 417 (2002).