Hey guys., I'm kind of lost here. My HDD, a four-year old Western Digital Caviar Black 640 gigs, SATA 2, and in the last days, I started getting checksum errors, and various read errors. I haven`t had problems with it until about now. I bought new parts to my PC, a ASRock 970 Pro 3, an AMD Phenom II 965 BE and a GTX 660 . I have a 4 year old 500W Akasa PaxPower so I should be fine with the PSU. When I installed the OS, I started having read errors from the "expanding files" stage in Windows 7 install. I had to try it 4 times to get it right. Then , after the install , I started having several read errors, several blue-screens and errors when I would use .iso files. Also , I get various checksum errors when checking with the .sfv files. Also , these errors appear on old files, not in the new only in the new ones. I don`t think it would be viruses. I did HDD checks in Windows and searched for bad sectors, also surface tests with different programs and found nothing bad. I`m at a loss. Any ideas? Is it a sign of the HDD failing ? Thanks.