So, has anyone had a problem returning software? I know that some retailers disclaimer their refusal to refund on PC games.
Depends what you mean by a problem. I've had a few stores refuse over the years, but I've only ever walked out without a refund twice, and on both occasions, a follow up letter/phone call to head office resulted in an apology, a refund and vouchers for compensation. There's no such thing as a disclaimer which is legally enforceable, even if they make you agree with it when buying the game.
What they actually do most of the time is try to misrepresent an existing law to cover something it doesn't. The law says that shops cannot resell a game which has been returned. This dates from the days of floppy disks when software could be infected with a virus before being returned to the shop. They will often try to tell you that this means they cannot accept returns on software, but it's a lie. If you're returning software which is faulty, they're not permitted to resell it, so it's entirely irrelevant. If you're polite but insistent, you won't go far wrong.