Hard drive yes, operating system maybe. Win 8 is due out soon, and Win 7 is very likely to get cheap quite quickly.
That being said, if you have a clean key and install media, you can call MS and ask to have the key moved to your new system which will remove the activation from your old system.
Don't bother trying to actually use the installed version, and fixing things. If you have a new system start it out right with a clean win install.