Mr O'Reilly told BBC Radio 5 live that the timing of Blockbuster's closure, shortly before Christmas, was "purely coincidental".
He added: "We really did try our best to find a buyer, but that, unfortunately, hasn't proved possible."
The rapid rise of online film streaming offered by the likes of Lovefilm and Netflix made Blockbuster's video and DVD business model practically obsolete.
The most recent closures follow on from previous closure announcements in November.
Blockbuster, the trading name of TS Operations, is currently owned by private equity firm Gordon Brothers Europe.
Moorfields said high business rates had contributed to the video company's demise.
Before its troubles began, Blockbuster had 528 stores.
Blockbuster is one of several High Street names to have been affected by online competition, including camera chain Jessops, music and DVD group HMV, and electrical chain Comet.