Lost System Keychain password

[aikdaman]

I recently had my Macbook Pro repaired and when it returned I realized I had forgotten my password. I used the install disc to reset the login password, but this did not change my system keychain password. I now can log on and use my Mac but I am unable to change any system settings due to this. I am operating on Mac OS X 10.4.11. I have Googled just about everything I can think of and found some tutorials on changing it in Terminal but none have worked, it continues to ask me for the password. I have also tried to delete it manually and in Keychain access without any luck. Would using the install disc and resetting the System Administrator(root) password work? If not, is there anyway to reset the system keychain?