The 2000 election was a mess because the voting system in Florida was horrid.

2004 on the other hand has a high possibility of Fraud. I have seen sources, but unfortunalty I'll be lazy and show a quote from Wikipedia

Quote Originally Posted by Wikipedia
Walden O'Dell the former CEO of Diebold (the parent company of voting machine manufacturer Diebold Election Systems) was an active fundraiser for George W. Bush's re-election campaign and wrote in a fund-raising letter dated August 13, 2003, that he was committed "to helping Ohio deliver its electoral votes to the President."
Also a note is the same company provided the voting machines during Alaska's elections that resulted is Sarah Palin becoming Governor.