Antisocial Hardware?

87C751 asks: "Over the weekend, I happened upon a deal: 10/100 PCI NICs for $1.99. I bought two and installed one in my Linux box. The box came up to POST, and the new NIC started looking for a DHCP server (which I thought was cute, if useless). Once that timed out, boot sequence continued to the message "NTLDR not found"! In an attempt to do a PXE net boot, the new NIC had -rewritten my boot sector!- Granted, a few minutes with a GRUB boot floppy set things right again, but why in the world is J. Random piece of hardware arrogant enough to frob my disc? Has anyone else been bitten by antisocial hardware?"