What do you mean by "exept operating system"?
What are you trying to do? Install the operating system?
If so, what operating system do you want to install? And what version?
That computer was made around 2005 and came with Windows XP. It should be able to run Windows 7 32 bits, maybe not with all features enabled, probbably not Windows 8, and only a 32 bits version if doable at all.
It should be able to run most distribution of Linux as long as it have a 32 bits version.
Do you have a DVD unit?
Recent operating system are now comming on DVD, not CD. If you have a CD reader, it won't be able to read any DVD.
Do you have AT LEAST 50 Gb of free disk space?
Windows 7 demand at least 50 Gb free disk space for the installation. Most of that space will be released once the installation is finished.
You need the 32 bits version of the operating system you want to install. As you have a 32 bits CPU, it's impossible to install any 64 bits OS.