This is a blinded (participant and study staff will not know the identity of assigned treatments), randomized (participants assigned to treatment by chance), placebo-controlled (a term used to describe a method of research in which an inactive substance referred to as a placebo is given to one group of participants, while the treatment being tested is given to another group) study to assess the effectiveness, safety, tolerability, and pharmacokinetics (to test the concentration of study drug in the blood over time) of different dose regimens of TMC435350 (hereafter referred to as TMC435) given alone or in combination with peginterferon alpha-2a (PegIFNa-2a) and ribavirin. TMC435 is a new drug that is development for the treatment of Hepatitis C virus (HCV) infection and belongs to a class of drugs that work by blocking an enzyme (protease) that the HCV needs to replicate. The combination of PegIFNa-2a and ribavirin are current standard of care (SoC) therapy for patients with chronic HCV infection. Approximately 72 participants with HCV infection who have never been treated for HCV infection (referred to as treatment-naïve participants) and 36 participants who have been treated for HCV infection (referred to as treatment-experienced participants) who did not respond to previous therapy with interferon (IFN) and who did not discontinue previous anti-HCV therapy because of adverse events \[AEs\]) will be included in this study. Two blinded placebo-controlled groups (referred to as "cohorts") of treatment-naïve participants will be sequentially initiated TMC435 to ensure that a higher dose is only administered if the previous lower dose is found safe and tolerable. The first group (Cohort 1) of treatment-naïve participants will receive low-doses of TMC435 or placebo for 7 days followed by 21 days of combined tritherapy with PegIFNa-2a and ribavirin OR participants will receive 28 days of tritherapy (TMC435 or placebo + PegIFNa-2a and ribavirin). After review of data from Cohort 1, a second group (Cohort 2) of treatment-naïve participants will be given higher doses of TMC435 or placebo in the same manner described for the first cohort. A third group (Cohort 3) of participants previously planned in the study will not be enrolled. After review of data from Cohort 2, a fourth group (Cohort 4) of treatment-experienced participants will be given 28 days of TMC435 (or placebo) as tritherapy with PegIFNa-2a and ribavirin to determine the maximum tolerated dose of TMC435. In addition, up to 10 HCV-infected individuals (who participated in study TMC435350-TiDP16-C101 (ClinicalTrials.gov registry number NCT00938899) will comprise Cohort 5 and will be given 28 days of TMC435 at a dose previously determined to be safe and efficacious as tritherapy with PegIFNa-2a and ribavirin. Blood samples will be taken from participants at protocol-specified time points to determine plasma concentrations of TMC435 and ribavirin and safety will be monitored throughout the study. Individuals will participate in this study for up 54 weeks (includes up to 6 weeks during the screening period followed by up to 4 weeks of study treatment with TMC435 (or placebo) and up to a maximum of 44 weeks of treatment with PegIFNa-2a and ribavirin.