What model is you PC? It is a desktop, -right?
What stuff did you repair? Fried wires?
This PC has a COA product key for Vista?
If you have a second PC, and can get on the Internet, you get a copy of Vista equal to the one you had.
Let's say it was a Dell Inspiron, of something like that.
The above is a DVD for sale by somebody for under $25. But it requires you to have a Dell COA. Otherwise it will not help much.
Also, VISTA DVDs for HP are available.
The alternative is to download a copy from a legal server. You still have to have the Dell COA.
Better yet, borrow a copy from a friend that has the same brand. If you have the product key, it is legal to borrow a DVD from somebody. But only if it is for the same brand.
Does that help any?
If you decide to buy a Vista DVD at retail, consider getting Windows 7 instead.