I'm a Spanish citizen and I was denied entry to the US 7 years ago because they found out I had been working after being admitted under the Visa Waiver Program (VWP). They banned me for 5 years. Now I want to go back as a tourist for a few days with my partner and I'd like to know what should I do and whether or not I have any chance of getting a visa.
Even if we knew the complete details of your ban, and the complete details of your current situation, and the complete details of a future US visa application — which we don't — the answer to "any chance?" would still be an opinion.
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The only way to know the answer is to apply, and to answer truthfully all the questions put to you.
As the ban has now lapsed, you can apply for a visa. But of course, officers examining your application will know about your previous violation and ban, so you start with a negative impression.
You'll have to fight hard to convince them that they should grant you a visa. Your application should be bullet-proof, with very strong ties to your home country (i.e. at the very least a stable, well-paid job, so you don't need to start looking for one in the US), an itinerary consistent with your stated reason for the visit, etc.
Still, they could decide outright that given your history they don't trust you whatever you say, however nobody but them can tell you that.
Since visa waiting times are currently over a year, it could make sense to delay the application until they come back to normal. Planning a holiday a year in advance is probably unusual (especially for "a few days"), and you'll have more difficulty in providing a consistent picture.