I have been out of high school for 5 years now, and I am looking into going into college. I did not take the SATs or the ACTs during High School. Will applying to colleges without having those scores be a problem? Will I have to take either of the tests?
Currently, for most 4-year colleges in the United States, you'll need to submit SAT or ACT scores. There are some schools which are test-flexible (meaning that you have an option of which test scores to submit), and some schools that are test-optional (meaning it's up to you whether or not to submit the scores), but the only 4-year college that is "test-blind" (meaning it absolutely doesn't want your test scores and taking the SAT or ACT will give you 0 advantage in the admissions process) is Hampshire College.
Some schools have programs specifically geared towards non-traditional students, or students who don't fit the typical high school senior profile, that do not require SAT or ACT scores. One such program is the School of Professional and Continuing Studies at Fordham University, which requires applicants to take Fordham's "College Skills Assessment" as part of the application process but does not require the SAT or ACT. At the College of Liberal and Professional Studies at the University of Pennsylvania, standardized test scores are usually not required for BA programs, although "you may choose to submit standardized test scores in support of your application." Even though neither of these programs explicitly requires the SAT or ACT, however, you'll note that you can submit SAT/ACT scores for UPenn to strengthen your application, and you have to take an SAT/ACT substitute for Fordham.
There are also some special circumstances when taking the SAT or ACT might not matter for college admissions. If you're applying to a community college or trade school, you probably won't have to submit SAT or ACT scores (although you'll need to check with individual schools for their particular policies). Similarly, many conservatories (for art, music, dance, film, and so on) require a portfolio showcasing your work, rather than standardized test scores.
For more information on this, I recommend also reading my answer to the question "Can I get into college if I refuse to take the SAT or ACT?"