Hi. I'm making a gaming PC and I have a budget of about 273 dollars. I have a HARD Drive with Windows 7 installed. I heard that you should re install windows if you put it in another system. However, the disk I used to install it was thrown out. How do I reuse this drive?
Thanks!Well, you still need to reinstall Windows - Do you not have the licence key/sticker for the installed COPY of WIndows?  If you can do you can try and borrow another disc with the same edition of Windows on it and use your key with it.  However, if the licence came on a prebuilt PC (i.e.  a sticker on the PC case) and not in a full retail box, it cannot legally be transferred to a new machine.

Also, unfortunately $273 is nowhere near enough to build a gaming PC.It's a computer I built. Is there a Microsoft Windows ISO that I can get?
Edit- apparently I bought an OEM copy and it doesn't accept a ISO download.
Unfortunately OEM copies cannot be legally moved to a new motherboard other than a like-for-like replacement if the original board has failed.Microsoft is changing all the license rules for Windows 10.  If you have Windows 7, it will be eligible for a FREE upgrade.  Microsoft stopped issuing product ID's (PIDs) with Windows 8.  It is still not clear how all this will occur, but they have announced a release date of 7/29/15.  Wait another 6 weeks to find out.It is unclear whether upgrading to Windows 10 would change an OEM license (tied to a machine) into a Retail license (allowing it to be used on other systems).