Oracle XE ( Express Edition ) does not exist for windows 64 bits ( the link in the prvious post links to Standard Edition, Standard Edition One, and Enterprise Edition ).
If you want to use 64 bits on XE you have to switch to linux ( e.g. Redhat/CENTOS etc ), or use a commercial edition of oracle which isn't free.
You can install XE 32 bits for windows on a 64 bits system, this isn't supported but it works and I've been using it like that for a long time.
You might run into one or two errors during installation but if you google those they are easy to fix ( and usually you can even just ignore them ).