hi i have a toshiba sattelite l300d laptop or a l300d-13s it changes from website to website , i have an ati radeon 3100hd series and an amd turion x2 . i have recently installed windows 7 professional by downloading it as it is the x64 student version . when unpacking the box i was getting an error right at the end buy found others were too , i converted the file to an iso mounted to a disk and thought no more of it . for a few days it was fine no worrys , now on startup i get error codes that normally read STOP: c000021a fatal system error something something unexpectidly with a status of 0x00000000(0xc0000001 0x00100588) i can often get my laptop to start up by continusaly trying "disable driver signature enforcement" or "debugging mode " but this will take sometimes 20 bootups . i have contacted microsoft but they were no help at all and didnt seem to understand the fact that it doesnt restart . i have run startup repair and it seems to think the root cause is a corrupt boot file it give this reading "bug check c000021a parametres = 0xfffff8a00011e500,0xc0000189,0x0,0x0 boot file is corrupt repair attempted = file repair failed error = 0x2 i have had the problem for ages and do not wish to reinstall the operating system if there is another way , i have ordered a windows 7 backup disc for an extra Ã‚Â£9 which has arrived in case that is of any relavence , any ideas?