Is it possible to change default OS at boot?

This is the snapshot from my desktop.

That looks good.

What, if anything, is on D, E, or F that you need?

Which of them has your data?

You need to enlarge C, but not this minute.

D, E and F have the data I need. Some of it is work related and some of it is pictures and movies which are anyway in an external drive and can be deleted.
My C drive however has less space so I am wondering what all I could delete esp from my windows.old folder for now..

Thank you all for your patience, kind help and advice. It was very helpful and guided me through this problem.

Good that you mentioned windows.old.

How big is that folder? A normal clean install of Windows should take up no more than 20 GB. Your C now has about 36 used out of 39. I assume windows old is most or all of the difference, but it's peculiar to me that you have a windows old if you did a clean install.

At any rate: how much space does ALL of your data take up? I don't mean backups. Just one original copy of everything. Excluding installed programs and Windows per se.

I assume you want to end up with C for Windows and D for data and nothing else?

You can delete partitions, but we need to get all of your data on one partition if possible first. So we need to know the size of it.

There is one windows.old and another windows.old.000.
the windows.old is 19.8GB and the windows.old.000 is 8.21GB.
The windows.old has all the program files and the exe which i used with win xp. but there is no program per se in windows.old.000
I am sure the windows.old.000 was not there when i did the first win 7 installation and i presume it has now written it when i reinstalled win7 again.
can i simply shift+del the windows.old.000 folder ? i dont see anything useful in it except for lot of default windows application like media player,games and internet explorer.
I see there is no clean install happening here.. it looks to me it is taking a back up of existing os and installing the win7 OS. is that normal?

Answer the questions about your data size.

Like this:

3 GB on F, 14 GB on E; 10 GB on D.

If worse comes to worse you do yet another Windows install. As you found out, it takes only 20 minutes.

Do you acknowledge having to reinstall all programs?

Hi,
well each drive is about 40GB in size. All of which have been saved to an external drive. The data I use day to day would be 5-8 GB on each drive and hence remaining space can be utilized for anything else.. or kept free.

Poolemahu said:

Hi,
well each drive is about 40GB in size. All of which have been saved to an external drive. The data I use day to day would be 5-8 GB on each drive and hence remaining space can be utilized for anything else.. or kept free.

I'd delete that windows old that you think was made in the last hour or two when you reinstalled Win 7 tonight.

Confirm the PC will re-boot and that you then have a bunch of freed up space on C.

Then post another screen shot.

What do you want to end up with??

C only? C and D? C, D, E, and F?

I'm wondering why you have split the drive up so much?

Well, i didnt split it by myself. Many years ago, when it was first bought or assembled, it was being shared by three of us. so the person putting the system together came up with this idea that each have a drive of his own and thus we ended up having 3 partitions. the C drive was always the OS drive.this machine later ended up being with me and not knowing so much about disk partition I left the stuff be as it is..
personally I can be happy with just C and D. In my earlier machine I had just C and I lost everything during an OS crash. So now I have an OS drive and anything else is stored on other drive(s).

i tried deleting the windows.old.000 and it doesnt allow me to do that.. it says the files are a system file or says that I need permission from "TrustedInstaller" to make changes to dll files.
I am the administrator for the machine and there are no other accounts.