C drive maxed out after vista reload

I recently had to reload vista the old os would no longer boot (malware?) After the reload everything looked good,fast again, until I started downloading stuff. A baloon opened and said I have low disk space. I opened c drive and it showed only the few things I had downloaded since reloading vista. How do I see what else is there (10 gb) and delete.
I'm a newbe and pretty much computer illiterate please be gentile.

 

Do you remember formatting and partitioning to reload? As for seeing what else there is open "Computer" and run cursor across drive C and look down to the left and you will see size of drive and how much is free.

 

I did click on a format button at reload. Now when I open C it only displays my new stuff which is only a few mb. The rest of the 10gb is not displayed. I assume it's my old vista OS and programs which I would delete

 

Something is wrong here as Vista alone can be 18 gb. What size drive and what is showing "not used"

 

I have a total of 120 gb. 60 gb open in D. C is full. I need to make room in C. What do I do? Should I try to load vista again and make sure I format before install.

 

Right click "Computer" choose "Manage", then "Disk Management". Right click D and choose "Expand Volume". The other choice would be to delete D, then expand C.
I know that Disk management in Vista can do it, I just have never done it. If you had 3rd party software like Acronis Disk Director the approach would be much more straight forward.

 

No luck, when that window opens EXTEND volume... is greyed out for both C and D drives.

 

You have to delete the D partition for it to work. It can only work with unallocated space.