Glioblastoma is an aggressive type of brain cancer. Standard treatment usually includes three weeks of radiation therapy alone or combined with chemotherapy using Temozolomide. After a four- to six-week break, more Temozolomide chemotherapy is usually given. However, some tumors have a marker ("unmethylated MGMT") that predicts the usual chemotherapy won't work. Because of this, this project will explore other treatment options to help slow the disease and improve survival. In this study, the same chemotherapy (Temozolomide) normally given after radiation therapy for glioblastoma. The only difference is that it will be given with a modified regimen.