"no bootable device" but fdisk list my drives

[gfirst]

on boot my pc says "no bootable device" insert and press any key.
using a live cd, i did 'sudo blkid' and got only '/dev/loop0'.
but when i did 'fdisk -l' i got:
"qimo@qimo-live:~$ sudo fdisk -l

Disk /dev/sda: 640.1 GB, 640135028736 bytes
255 heads, 63 sectors/track, 77825 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0xb778d9c5

This doesn't look like a partition table
Probably you selected the wrong device.

Device Boot Start End Blocks Id System
/dev/sda1 1 41017 329465857 f W95 Ext'd (LBA)
/dev/sda2 ? 41017 60599 157286400 7 HPFS/NTFS
/dev/sda5 12401 26124 110237096+ 83 Linux
/dev/sda6 * 1 2612 20971520 83 Linux
/dev/sda7 26125 27369 9999360 83 Linux
/dev/sda8 27370 31104 29999104 83 Linux
/dev/sda9 31104 37329 49998848 83 Linux
/dev/sda10 2612 9139 52428800 83 Linux
/dev/sda11 37329 41017 29627392 83 Linux

Partition table entries are not in disk order

Disk /dev/sdb: 2027 MB, 2027945984 bytes
255 heads, 63 sectors/track, 246 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000c5464

Device Boot Start End Blocks Id System
/dev/sdb1 * 1 246 1975963+ 83 Linux
"

what can i do. i think i have to restore my mbr or restore my partition table.

please help me

[darkod]

You can use fixparts or testdisk to sort out the partition table.

Something is confused with sda2. According to the start-end sectors from fdisk, sda2 is inside the extended partition sda1. But in that case it wouldn't be called sda2 because 1-4 is designated for primary partitions, and 5+ for logical.

Also you might reconsider having only logical partitions on the disk and no primary. I don't know if it matters, but the extended partition is a last option when needing more than 4 partitions. It doesn't mean you shouldn't have 3 primary first, before you started thinking about extended partition.

[oldfred]

There are a few BIOS (most Intel motherboards) that have to have the boot flag on a primary partition to let you boot at all. Basically it assumes Windows as that is a Windows requirement, but grub does not use nor need a boot flag.

[darkod]

I have to correct myself, the numbers are not lined up and I didn't see it right.
sda2 does seem to be outside, after sda1 but the fdisk message (one of them) is still "this doesn't seem like partition table". There is something wrong with the table it seems.

On top of it, as oldfred says, the boot flag is on sda6 and needs to be on a primary partition. Set it on sda2, linux doesn't care about boot flag anyway.