First off, some programs refused to open, fault errors came up in mirc, cuteftp pro, etc. and the interface on Paintshop pro and LiveUpdate went a bit f**ked as well as some other applications. Start Menu appeared weirdly, then my right mouse button sometimes stops working. So I ran chkdsk, it found the Volume Bitmap error, so I rebooted to fix it. Upon bootup, nothing at all would start, not msn messenger, not IE and about 30 services failed to load. So I rebooted again and all’s ok. I ran virus checks and HDD tests, one error came out of the HDD test and it suggested to low level format. I decided not to go any further since I didn’t have time to waste so I swapped the Hard drives with a spare one I had. I clean installed WinXP SP1 and all my applications, then all these problems noted above started happening again! Even stuff like my modem drivers got corrupted on bootup after running a full 5-step chkdsk. I've come to the conclusion that either hard drive isn't at fault here. Could it be the OS itself? I don't know, the most recent stuff I've installed is Diskeeper 7.0.427, Norton Antivirus Corporate 8.01, and Avant Browser (the 1st two being updated, and Avant Browser being used since 2 weeks ago). I've been suffering this problem for 2 weeks and I don't know what to do. I even put in a new IDE cable, but the chkdsk errors are still there. Running Chkdsk in WindowsXP SP1: (command: chkdsk c: /v) CHKDSK is verifying files (stage 1 of 3)... File verification completed. CHKDSK is verifying indexes (stage 2 of 3)... Index verification completed. Detected minor inconsistencies on the drive. This is not a corruption. CHKDSK is verifying security descriptors (stage 3 of 3)... Security descriptor verification completed. Correcting errors in the Volume Bitmap. Windows found problems with the file system. Run CHKDSK with the /F (fix) option to correct these. Running a full 5 step chkdsk before bootup reports no problems at all, it never did! It only seems to report the error when its in Windows. Specs: AMD 1.3ghz, 512mb ddr, ati radeon 7200, Maxtor 60gb (now taken out), replaced with IBM 40GB. My Western Digital on slave has been fine all throughout these problems I've had. I really have no idea what it is!