help my laptop keeps on crashing when i run an anti virus scan?

just recently whenever i run an anti virus scan on my dell inspiron 6000 it gets to the same point and freezes and after a few minutes i get a blue screen with this error message: a problem has been detected and windows has been shut down to prevent damage to your computer if this is the first time youve seen this stop error, restart your computer. if this screen appears again follow these steps:disable or uninstall any anti virus disk defrag or backup utilities. check hard drive config and check for any updated drivers. run chkdsk /f to check for hard drive corruption and restart your computer. tech info:***stop:oxoooooo24(oxoo1902fe,oxf8a6db6c,oxfa6d868,0xf83af8d6)***ntfs.sys-adress f83af8d6 base at f839e000,datestamp 48025be5. beginning dump of physical memory.physical memory dump complete contact system admin or tech support for further assistance. i am running avg2011 anti virus and have tried uninstalling it but the same happens. the chkdsk /f ran alright but seems to have made no difference. i have also tried to run microsoft malicious software removal tool which worked fine right untill the end when it froze and the same error msg appered. i am unsure how to uninstal disk defrag or how to get it back afterwards same with backup fac and i am also unaware as to run the hard drive configuration. also at around the same time the cd drive stopped burning cds, it will still read but refuses to write. i am unsure if this could be causing the computer to crash or if a problem with the hard drive is causing the burner to fail. it will cost me about £100 pounds to find out and seeing that the machine is nearly six years old i dont really want to spend a great deal on getting it sorted if it is something simple. thanks for your time in reading this problem.