OUTLINE: This is an open label, dose escalation study. Patients receive oral temozolomide once daily on days 1-5. Carboplatin IV is administered over 1 hour on day 1. Courses are repeated every 28 days. Treatment continues for a maximum of 6 courses in the absence of toxicity and disease progression. Sequential dose escalation of carboplatin with a fixed dose of temozolomide is followed by sequential dose escalation of carboplatin at a higher fixed dose of temozolomide. Dose escalation in cohorts of 3-6 patients each continues until the maximum tolerated dose (MTD) is determined. The MTD is defined as the dose preceding that at which 2 of 3 or 2 of 6 patients experience dose limiting toxic effects. If the combination treatment with carboplatin given on day 1 of temozolomide therapy is more toxic than anticipated, then the study is repeated with carboplatin given on day 5 of temozolomide therapy. Patients are followed at least every 2 months.