Microsoft Office 2000

Microsoft Office 2000 is basically Microsoft Word, Excel, Access (etc) in one suite. Removing Microsoft Office will remove those programs too. (considering you have only 300-odd Mb installed it looks like you installed just the basic files, Office usually is about 600Mb fully installed)

(EDIT: Just properly read what you typed. Office Premium is the same as Office Professional, but with extra programs. If you uninstall Office Premium then you may create problems since both Office Suites uses the same directory. Safest solution is to uninstall both Offices and then reinstall the Office Suite you want)

Try running the Disk Cleanup to help you remove unnescessary files like Temporary Files and Temporary Internet Files. Also determine you have any other programs that you don't really need, like if you have Windows Media Player and WinAmp, both does the same function, so choose which one you don't want.

Also if you have a CD Writer, backup any files you want to keep, i.e MP3s, AVIs or MPEGs (the most common and massive files) or your documents so you can delete them from your hard drive once you back them up on a CD.

Other than that, you may want to consider a new drive.

Hope that helps.