How do I reset my computer (vista) without a cd?

[GamerNoob]

So I want to reset my cd but I need a windows vista home premium cd because I lost mine and cant afford a new one.
So I dont know anything about this stuff but many told me I need a download link and an empty dvd cd I dont have both of them though.
These are the things I have right now.
A windows vista home premium key, an usb stick with 8 gb and a few cd roms with 750 mb each.

What to do? Please in detail because I suck at this.
english is not my native language so sorry if I sound impolite

 

[USAFRet]

After looking around, I have not found a valid, legal ISO for Vista.

 

[GamerNoob]

am I allowed to post links?

 

[hang-the-9]

Contact the PC vendor, they may have a restore set for your system, although they will likely charge you to ship it.