Blood tests (less than 2 teaspoons) will be repeated every 2 weeks and before each new cycle of treatment (a total of about 2 tablespoons). The neurological exam, anticonvulsant level blood tests and the stool test for blood, will be repeated before every cycle on Arms 2 and 3 (CCNU) and before every 2 cycles on Arms 1 and 3 (temozolomide). Kidney function will be evaluated from the blood tests before every other course. Patients taking anticoagulants (coumadin, warfarin) will have procedures to test the clotting ability of the blood before each cycle or more frequently if the doctor feels it is necessary.