Hi everybody, first of all sorry for my bad english if I made wrong sentences.

Im having some trouble about the warnings in my event log. There are two kind of warnings that I face usually (but I dont know why) and their ID's are 51 and 57. It says: Event ID - 51 - "An error was detected on device \Device\Harddisk1\D during a paging operation." I looked to my computer/manage/disk management and i saw that the disk 1 is my usb external hdd. Its seagate 1.5 tb free agent drive. The other warning is ID 57 and it says: "The system failed to flush data to the transaction log. Corruption may occur."
There were no 51 warnings before i bought my external, but i had 57's before i bought my external. Can someone tell me what all these warnings about and what should I do?

Thanks a lot and best regards...