hi, thx for reply
I forgot to metion that in order to install grub on boot drive, I installed a ubuntu on that drive, too
dev/sda3/ : my windows 7 installation
dev/sda4/ : data drive for windows
dev/sda6/ : ubuntu 12.04 installation
dev/sdb7/ : ubuntu 13.04 installation(not important, will format it if the problem is solved)
dev/sdb3/ : data drive for ubuntu 12.04(which I formated and mounted for ubuntu 12.04 at the time it still worked)
other ntfs partition on sdb is for data storage of windows 7
Code:
Disk /dev/sda: 120.0 GB, 120034123776 bytes
255 heads, 63 sectors/track, 14593 cylinders, total 234441648 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xd21767a9
Device Boot Start End Blocks Id System
/dev/sda1 2048 35096575 17547264 27 Hidden NTFS WinRE
/dev/sda2 35096576 35151871 27648 7 HPFS/NTFS/exFAT
/dev/sda3 * 35151872 146303954 55576041+ 7 HPFS/NTFS/exFAT
/dev/sda4 146320017 234440703 44060343+ f W95 Ext'd (LBA)
/dev/sda5 146320080 207816839 30748380 7 HPFS/NTFS/exFAT
/dev/sda6 207818752 226371583 9276416 83 Linux
/dev/sda7 226385920 234440703 4027392 82 Linux swap / Solaris
Disk /dev/sdb: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x566b9230
Device Boot Start End Blocks Id System
/dev/sdb1 2048 37750783 18874368 27 Hidden NTFS WinRE
/dev/sdb2 * 37750784 37955583 102400 7 HPFS/NTFS/exFAT
/dev/sdb3 38186552 976768064 469290756+ f W95 Ext'd (LBA)
/dev/sdb5 38186554 425449394 193631420+ 7 HPFS/NTFS/exFAT
Partition 5 does not start on physical sector boundary.
/dev/sdb6 507364893 976768064 234701586 7 HPFS/NTFS/exFAT
Partition 6 does not start on physical sector boundary.
/dev/sdb7 425449472 507363327 40956928 83 Linux
Partition table entries are not in disk order
Disk /dev/sdc: 4043 MB, 4043308544 bytes
255 heads, 63 sectors/track, 491 cylinders, total 7897087 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x91f72d24
Device Boot Start End Blocks Id System
/dev/sdc1 * 63 7897086 3948512 c W95 FAT32 (LBA)
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