At 5 p.m. today, the sounds of Nirvana's "All Apologies" blasted out of stereos set to 92.3 FM which officially marked the station's return to WXRK, or K-Rock, after last year's switch to WFNY FreeFM. Rumors of famous shock-jock hosts Opie And Anthony's firing were also put to an end, as they kicked off the first "rock block" declaring "K-Rock is back," before launching into Guns And Roses' "Welcome To The Jungle." With ratings decreasing over its course, as well as the departure of CBS Chief Exectutive Joel Hollander, change seemed inevitable. The move to change WFNY to WXRK is the first major change since new Chief Executive Dan Mason started last month. FreeFM had its fair share of problems in its short run, where the station was faced with an empty slot once Howard Stern left for SIRIUS satellite radio. A brief stunt with David Lee Roth as a morning show host only lasted until April, when he was replaced by shock-jocks Opie And Anthony. Recent attacks from various ethnic and lifestyle groups resulted in a 30-day suspension of the notorious duo on XM radio, but not by FreeFM parent company CBS. But CBS did fire fellow FreeFM hosts JV And Elvis, who were brought under fire after calling young band A Brief Smile "faggots." But it was a prank call to a Chinese restaurant with a plethora of sexual slurs that finally got them fired. Under the new formatting, Opie And Anthony will continue their morning show; rock music (emphasizing artists from the 1990s to today) will take over from 9 a.m. onwards. www.923krock.com