OS in external harddrive not recognised

hello! folks!
straight to the point,
my computer was f'ed up last week.boot mgr is missing in my hard drive and what i did was installed a new OS into an external harddrive with my laptop by this process How To Install Windows 7 On USB Flash Drive or External Hard Drive and everyhting was good,installed the OS onto hardrive perfectly. but when i plug that to my PC it wasnt getting recognised,i mean it directly goes to installation ;[. and asks me to install it. i've set the first boot option to usb-fdd and restart and the same thing happens. i dont understand what to do now!! please gimme a solution about how to boot OS with the external hdd which has an OS installed and my harddrive as a storage,,
thnx in advancee!

yes, i do have that system reserved option and its 350mb!
could you tell me how do u do that system recovery (yes iam a noob :[) three seperate times??
there is no OS to select there btw!! as i've told you i formatted my c drive and tried to install a new one this problem has comeup!!!
thnx in advance!!

Is the System Reserved partition marked Active? Partition - Mark as Active (Method Two)

Once you confirm it's set Active then boot into the Win7 installation Media or System Repair Disk to run Startup Repair - Run 3 Separate Times .

If you need help on any set click the blue link to read how to do it.

Ask back if you have any specific questions.

If after confirming Active partition the OS still doesn't show up for repair, from the System Recovery Options open a Command Prompt, type:

bootrec /fixboot
Bootrec /fixmbr

Then try Startup REpair again up to 3 separate times to see if it will repair.

If this fails, start at the top to work through the steps for Troubleshooting Windows 7 Failure to Start.

Everything that can be done to start unbootable Win7 is there, leading up to if necessary rescuiing your files to the external HD to do the superior Clean Reinstall - Factory OEM Windows 7

gregrocker said:

Is the System Reserved partition marked Active? Partition - Mark as Active (Method Two)

Once you confirm it's set Active then boot into the Win7 installation Media or System Repair Disk to run Startup Repair - Run 3 Separate Times .

If you need help on any set click the blue link to read how to do it.

Ask back if you have any specific questions.

If after confirming Active partition the OS still doesn't show up for repair, from the System Recovery Options open a Command Prompt, type:

bootrec /fixboot
Bootrec /fixmbr

Then try Startup REpair again up to 3 separate times to see if it will repair.

If this fails, start at the top to work through the steps for Troubleshooting Windows 7 Failure to Start.

Everything that can be done to start unbootable Win7 is there, leading up to if necessary rescuiing your files to the external HD to do the superior Clean Reinstall - Factory OEM Windows 7

thank you so much for the information sir! and btw i've put my installation usb stick and opened cmd using shift+f10 key and then opened notepad and found 2 backup files named backupset 2013-08-07 and another one is backup sat 2013-06-13 and inside those files there are some backupgiles with some dates and another folder named cataloges..is this a backup file????!!!!!!!!!!! if yes how do i backup my pc with those files..
please reply ASAP
thanking you in advance!!!

Those do not sound like any kind of backup of a system image or files which would be useful.

What about the steps I gave you? Are you performing them now? Why not?

gregrocker said:

Those do not sound like any kind of backup of a system image or files which would be useful.

What about the steps I gave you? Are you performing them now? Why not?

yep i finally did this . i opened up cmd while windows installation and attached my external hdd opened notepad and the transferred all of my data (how much ever i could) and then wiped the whole hard drive and reinstalled windows and dumped back all of my data back into it!!
thanks you for the reply gregrocker!!! that helped a lot!!

im trying to clone my windows 7 on to a sshd drive that is currently in a caddy waiting to be detected but the laptop can't see it. i went in to the manager on c drive and it's there, but doesn't give any options for formatting . i need it to be recognized on plug in so I can run the software and get it plugged in place of my other drive. This is doing my head in. Please help if you can.

How is the drive plugged into laptop? It may need to be plugged in internally. Can you apply the image connected via external HD using a boot disk to the target machine?

i ended up pressing where i was in disc manager and as it could find the drive only threw the manager i had to right click and applying some i forget now as I rang up Maplin where i got the kit from and he told me to apply then i could call the drive what i like then it recognized the drive once i came out. i then cloned the drive and it works great. thanx for getting back so fast . iv been on this for couple of day untill i decided to ring maplin. great kit ocz ssdupgrade kit.