I am trying to determine possible causes for the above blue screen error. Here's the situation: the computer is a 6 month old Dell Inspiron 530. My company has 6 of them and we use them to print bar code labels, each on its own dedicated bar code printer. 5 of the machines work great, however, one computer tended to freeze up and/or give us lots of error messages. I paid to have the store run hardware diagnostics on it and the hardware came back with no problems detected. I also ran check disk to make sure the hard drive didn't have errors and it also came back as fine. Concluding that the operating system somehow was corrupted, I reformatted and reinstalled everything. It worked fine until the bar code software guy installed the printer driver and bar code software. The very next day, we then received the c000021a error. When I rebooted the computer, it worked fine again and now seems to continue to run ok! I asked the bar code label software company guy about the error and he immediately said that it was a Window's XP problem and disavowed any possible responsibility..... When I googled the c000021a error code, I found that there seems to be all sorts of possible causes ranging from boot up problems to sunspots! I did find one forum which stated that printer driver conflicts could cause this type of error. Assuming that this seemingly intermittent problem will occur again, I'm writing to see if you can give me a definitive explanation on this type of error and its causes and if driver conflicts could indeed be a potential cause. Thanks very much!!